Birthdates of the Harry Potter characters

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Birthdates in the Harry Potter universe:
an examination of what we know or can deduce about the dates of birth of various Potterverse characters, with an explanation for the apparent anomalies relating to dating Charlie Weasley. For a summary listing known or surmised dates for all characters, jump to end.

Birthdays:

Birthdays on JKR's website
Name	Day	Month
Severus Snape	9	January
Arthur Weasley	6	February
Ron Weasley	1	March
Remus Lupin	10	March
Fred & George Weasley	1	April
Pomona Sprout	15	May
Draco Malfoy	5	June
Dobby	28	June
Neville Longbottom	30	July
Harry Potter	31	July
Ginevra Weasley	11	August
Percy Weasley	22	August
Hermione Granger	19	September
Minerva McGonagall	4	October
Filius Flitwick	17	October
Molly Weasley	30	October
Bill Weasley	29	November
Rubeus Hagrid	6	December
Charlie Weasley	12	December

JK Rowling's official website opened in May 2004. Starting from July 2004 onwards, the website has posted annual birthday greetings and e-cake to various characters from the Harry Potter books. By this method, she has established birthdays for many of the major characters. Some of these are also confirmed in the books.

Birthdays derived from the books
Name	Day	Month	Comments
Lily Evans	30	January
James Potter	27	March
Dudley Dursley	30	June	or 23^rd June
Tom Riddle	31	December

In addition, internal evidence in the books sheds light on some other birthdays which are not on the cake-list, although in the case of James Potter that evidence is conflicting.

James really ought to have been born some time between early June and the end of August, because the bullying incident which Harry saw in the Pensieve took place during James's OWLs, which would normally be held during the first two weeks in June in the students' fifth year, when they were either fifteen or sixteen, and Lupin says that James was still fifteen at that point.

Harry moved around behind Snape and read the heading of the examination paper: DEFENCE AGAINST THE DARK ARTS -- ORDINARY WIZARDING LEVEL.
So Snape had to be fifteen or sixteen, around Harry's own age. [OotP ch. #28 p. 564/565]

Then Lupin said quietly, 'I wouldn't like you to judge your father on what you saw there, Harry. He was only fifteen --' [OotP ch. #29 p. 590]

James Potter, born 27 March 1960, died 31 October 1981
Lily Potter, born 30 January 1960, died 31 October 1981
[DH ch. #16; p. 268]

But either JK just forgot about that or Lupin was getting mixed up, because the tombstone at Godric's Hollow in Deathly Hallows states flatly that he was born on the 27^th of March (and Lily Evans was born on 30^th January). Perhaps Lupin was susbconsciously thinking of the werewolf "prank", which you would think would prey on his mind rather; in which case this would be evidence that that incident occurred prior to the 27^th of March.

'New Year's Eve and bitter cold, snowing, you know. Nasty night. And this girl, not much older than I was myself at the time, came staggering up the front steps. Well, she wasn't the first. We took her in and she had the baby within the hour.' [HBP ch. #13; p. 249]

Tom Riddle's birthday is quite definite. HBP clearly states that he was born on New Year's Eve, or just possibly on New Year's Day, depending on how late on New Year's Eve his mother arrived at the orphanage. JKR was asked about this on her website, and said New Year's Eve.

[cut] Harry and Uncle Vernon watched Dudley unwrap the racing bike, a cine-camera, a remote-control aeroplane [PS ch. #02; p. 21]

It was a very sunny Saturday and the zoo was crowded with families. [PS ch. #02; p. 24]

The month-old cine-camera was lying on top of a small, working tank [PS ch. #03; p. 32]

Next morning at breakfast, everyone was rather quiet. [PS ch. #03; p. 32]

The repaired alarm clock rang at six o'clock the next morning. [PS ch. #03; p. 33]

On Friday, no fewer than twelve letters arrived for Harry. [PS ch. #03; p. 34]

On Saturday, things began to get out of hand. [PS ch. #03; p. 34]

On Sunday morning, Uncle Vernon sat down at the breakfast table looking tired and rather ill, but happy. [PS ch. #03; p. 34]

'It's Monday,' [Dudley] told his mother. 'The Great Humberto's on tonight.' [PS ch. #03; p. 36]

The lighted dial of Dudley's watch [cut] told Harry he'd be eleven in ten minutes' time. [PS ch. #03; p. 38]

'[Harry's] a month younger than Dudley' [HBP ch. #03; p. 56]

Dudley Dursley's date is more approximate, and is based on calculations given on the Harry Potter Lexicon. We know that Dudley received a cine-camera for his eleventh birthday, which was a Saturday. We know that Harry's birthday was July 31^st. The day before Harry's birthday was the day they woke up at the hotel and all rowed out to the island, and it was a Monday, so Harry's birthday was a Tuesday (in Rowling-time: in real life it was a Wednesday).

The day before they went to the island was the day they left home and drove to the hotel, which is confirmed as a Sunday. Saturday and Friday are also specified. The day before that, which was the day Harry trod on Vernon's sleeping face, was therefore a Thursday. The day the letters began arriving addressed to Harry in The Smallest Bedroom was the Wednesday and the day they first started arriving was Tuesday 24^th July, one week before Harry's birthday - and it was on that day that Harry moved from his cupboard to Dudley's second bedroom. On that day, he saw the cine-camera and thought of it as being a month old, so Dudley received the camera approximately five weeks prior to Harry's birthday.

Dudley's birthday was therefore round about 24^th June, if Harry means the camera is a calendar month old, or 26^th June if he means it's four weeks old. The 26^th of June, being four weeks earlier than the 24^th July, would also have been a Tuesday (Rowling time). Dudley's birthday was on a Saturday so it would have been either 23^rd June or 30^th June. The Lexicon has plumped for 23^rd June because it is the closest Saturday to 24^th June. I'm more inclined to go for 30^th June because it fits better with Petunia's statement that Harry is a month younger than Dudley.

The escape of the Brazilian boa constrictor earned Harry his longest-ever punishment. By the time he was allowed out of his cupboard again, the summer holidays had started and Dudley had already broken his new cine-camera [PS ch. #03; p. 28]

A birthday on the 30^th June also reduces the otherwise improbably long time Harry spent confined his cupboard (although not locked in, since he raided the kitchen at night) after the snake incident, since we know he was shut in (at least in the evenings: we don't know whether he was still going to school or not) from the evening of Dudley's birthday until after school ended for the summer, which would be in the third week in July.

... he watched the younger of the two girls swinging higher and higher than her sister.
'Lily, don't do it!' shrieked the elder of the two. [DH ch. #33; p. 532]

For Petunia, we do not have a birthdate: we know only that she's visibly older than Lily, but not too old to play on the swings with her, so probably two or three years older. But a firm birthdate has been stated for Vernon - 11^th September 1956 - although I haven't found the location where this was originally given or by whom (so it's possibly fanon), and Rowling has said that Petunia was initially Vernon's secretary.

As the next day was Saturday, most students would normally have breakfasted late. [GoF ch. #16; p. 228]

       The decorations in the Great Hall had changed this morning. As it was Hallowe'en, a cloud of live bats was fluttering around the enchanted ceiling [cut]
       'Are you seventeen, then?' asked Harry. [cut]
       'I had my birthday last week,' said Angelina. [GoF ch. #16; p. 229/230]

In addition, we know that Angelina Johnson was born in the last week of October, since she turned seventeen during the week prior to the Hallowe'en in GoF (and that Hallowe'en was a Saturday in Rowling-time, so there's no ambiguity between "the previous calendar week" and "the previous seven days").

Wood had pointed out Cedric Diggory to him in the corridor; Diggory was a fifth year and a lot bigger than Harry. [PoA ch. #09; p. 131]

Cedric Diggory was an extremely handsome boy of around seventeen. [GoF ch. #06; p. 67]

[cut] the selection of the three champions will take place at Hallowe'en. [cut]
'Eager though I know all of you will be to bring the Triwizard Cup to Hogwarts,' he said, 'the Heads of the participating schools, along with the Ministry of Magic, have agreed to impose an age restriction on contenders this year. Only students who are of age - that is to say, seventeen years or older - will be allowed to put forward their names for consideration.' [GoF ch. #12; p. 166]

By the time Harry reached the bottom of the marble staircase, Cedric was at the top. He was with a load of sixth-year friends. [GoF ch. #20; p. 297]

We also know that Cedric Diggory was one of the oldest students in his year, with a birthday probably in early September. We know that he was a fifth-year in PoA so he was a sixth-year in GoF, and this is confirmed by the fact that he had a group of friends in sixth-year. He had to have turned seventeen by Hallowe'en of GoF in order for his name to be entered into the draw for the Triwizard Tournament, but in any case we are told that he was "around seventeen" at the World Cup.

But there was still a fortnight to go before he went back to school. [GoF ch. #02; p. 24]

[cut] the final of the Quidditch World Cup takes place next Monday night [GoF ch. #03; p. 32]

[cut] allowing Harry to disappear to the Weasleys' for the rest of the summer would get rid of him two weeks earlier than anyone could have hoped, [GoF ch. #03; p. 33]

By twelve o'clock next day, Harry's trunk was packed [GoF ch. #04; p. 39]

'You really should be in bed, the whole lot of you, you'll be up at the crack of dawn to get to the Cup.' [GoF ch. #05; p. 60]

Neither Mr Weasley nor Percy was at home much over the following week. [cut]
'It's been absolute uproar,' Percy told them importantly, the Sunday evening before they were due to return to Hogwarts. [GoF ch. #10; p. 135]

There was a definite end-of-the-holidays gloom in the air when Harry awoke next morning. Heavy rain was still splattering against the window as he got dressed in jeans and a sweatshirt; they would change into their school robes on the Hogwarts Express. [GoF ch. #11; p. 141]

The World Cup took place two weeks before the start of the autumn term 1994, which was presumably on September 1^st as usual. We know that term started on a Monday, and that the World Cup was on a Monday. It's ambiguous whether nearly-one or nearly-two weeks pass at the Weasleys' house between the day after the World Cup (a Tuesday) and the day before the start of term (a Sunday), but we know that Harry receives his invitation to the World Cup about two weeks before the start of term, that he set off for The Burrow the day after he received the invitation, and that the World Cup was the day after that. So he received the invition on Saturday 16^th August (Rowling-time) and the World Cup took place on Monday 18^th August.

At that time, Cedric can't have been quite seventeen, or he would have been going into seventh year, not sixth (unless he repeated a year). Yet, in order to be "around seventeen" he must have been very nearly seventeen, so his birthday was in September, and probably in the first half.

'He's unbelievable. He's really young, too. Only just eighteen or something.' [GoF ch. #07; p. 77]

It was hard to believe he was only eighteen. [GoF ch. #08; p. 95]

According to Ron, at the World Cup, Viktor Krum was only just turned eighteen, so if that's right we can assume he was born in July or early August, yet he was still a schoolboy the following academic year. If he was a Hogwarts student that wouldn't be possible, unless he was repeating a year, because a student whose birthday fell during the summer would be one of the youngest in his year and would finish NEWTs before his eighteenth birthday. But Durmstrang may set the barrier which decides which birthdates go into which academic year earlier than Hogwarts - perhaps August 1^st rather than September 1^st - or their course may be a year longer.

Birth years:

'Well, this Hallowe'en will be my five hundredth deathday,' said Nearly Headless Nick [CoS ch. #08; p. 99]

Sir Nicholas de Mimsy-Porpington
died 31st October, 1492
[CoS ch. #08; p. 102]

We know the years in which the books are set, because during the autumn (first) term of Harry's second year he attended a party to mark the five hundredth anniversary of the death of Nearly Headless Nick, and there was a banner proclaiming that Nick had died in 1492. We know, therefore, that Harry's second academic year was 1992/93. Harry started at Hogwarts in 1991 and he turned eleven that year, so he was born in 1980. This is consistent with his parents' date of death, which is given in Deathly Hallows as Hallowe'en 1981.

We know that pupils start at Hogwarts no earlier than the September 1^st after they turn eleven, because JK said on her website that "... you must be at least eleven to attend Hogwarts...." - although it isn't clear what happens if your birthday is actually September 1^st. But since that doesn't apply to any of the students whose birthdays we know, we can infer that if Harry was born in 1980 then Hermione was born in 1979 and Ron, Neville, Draco and Dudley in 1980. Everyone in Harry's year (unless they are repeating a year) was born between September 1979 and August 1980.

Looking up, he saw the very small, mousy-haired boy he’d seen trying on the Sorting Hat last night [cut]
       'All right, Harry? I'm - I’m Colin Creevey,' he said breathlessly, [CoS ch. #06 p. 75]
       'Creevey, Dennis!'
       Tiny Dennis Creevey staggered forward, tripping over Hagrid's moleskin [GoF ch. #12 p. 158]
       'No you're not,' said Ginny sharply. 'Neville Longbottom -- Luna Lovegood. Luna's in my year, but in Ravenclaw.' [OotP ch. #10 p. 169]
       'You're under-age!' Mrs Weasley shouted at her daughter as Harry approached. 'I won't permit it!' [cut]
       'She's sixteen!' shouted Mrs Weasley. [DH ch. #30 p. 486]
[cut] Colin Creevey, though under-age, must have sneaked back [DH ch. #34 p. 556]

Colin Creevey and Luna Lovegood are in the academic year below Harry, which means that in theory they could have been born any time between 1^st September 1980 and 31^st August 1981. However, we know that Colin was not yet of age (not yet seventeen) at the time of the battle of Hogwarts and an attempt is made to bar him from combat as a result. Ginny (who we know has an August birthday) is also told she's too young because she's not quite seventeen yet, whereas no-one suggests that Luna shouldn't be there; so we can assume that Luna was of age. Dennis Creevey is two academic years below his brother, since we first see him in GoF, but we do not have any other input on his age.

'My son, Draco, is home for his Easter holidays. [DH ch. #23 p. 370]

Harry stood quite still, eyes glazed, watching the place where a bright gold rim of dazzling sun was rising over the horizon. [cut]
'I need to speak to Griphook and Ollivander,' Harry said. [DH ch. #24 p. 391]

[cut] three days after they had arrived at the cottage [cut]
''Arry, Grip'ook would like to speak to you.' [DH ch. #25 p. 407/408]

Slowly, the days stretched into weeks. [DH ch. #25 p. 411]

'I'm sorry,' he told Fleur, one blustery April evening [DH ch. #25 p. 412]

It was a relief when six o'clock arrived and they could slip out of their sleeping bags, dress in the semi-darkness, then creep out into the garden, where they were to meet Hermione and Griphook. The dawn was chilly, but there was little wind now that it was May. [DH ch. #26 p. 421]

The battle of Hogwarts occurred early in May 1998. We know it was in May because it was the night after the raid on Gringotts, which was in May. We can surmise that it was early May because we know the fight at Malfoy Manor took place during the Easter holidays, so in late March or early April, and whilst the Trio then stayed at Shell Cottage for some weeks there is no suggestion of it being well over a month. According to Pottermore it was the night of 1^st/2^nd May, although the book text suggests it might have been a couple of days later.

So we know the battle was in early May, and therefore that Luna was born between 1^st September 1980 and early May 1981, and Colin between early May 1981 and 31^st August 1981. If Luna should happen to be one of the oldest pupils in her year she could be as little as four and a half weeks younger than Harry.

Angelina Johnson turned seventeen in October 1994, and Cedric Diggory turned seventeen in September 1994, so they must both have been born in 1977. Viktor Krum turned eighteen the same year Cedric turned seventeen, so he was born in 1976.

'Oh, are you starting at Hogwarts this year?' Harry asked Ginny.
She nodded, blushing to the roots of her flaming hair. [CoS ch. #04 p. 38]

Harry glanced back at the photograph. Percy, who was in his seventh and final year at Hogwarts, was looking particularly smug. He had pinned his Head Boy badge to the fez perched jauntily on top of his neat hair [PoA ch. #01 p. 13]

At that moment Mrs Weasley entered the bar, laden with shopping bags and followed by the twins, Fred and George, who were about to start their fifth year at Hogwarts [PoA ch. #04 p. 50/51]

Then we can work out the ages of the other Weasley children. When Harry is in third year Percy is in seventh year and the twins are in fifth year: so the twins were born in April 1978 and Percy in August 1976. Ginny starts school in Harry's second year so she was born in August 1981. [It may be worth noting that both Percy and Ginny are among the youngest students in their respective years.]

'Bill and Charlie have already left -- Bill was Head Boy and Charlie was captain of Quidditch.' [PS ch. #06 p. 75]

'Charlie's in Romania studying dragons and Bill's in Africa doing something for Gringotts,' [PS ch. #06 p. 80]

'It's great being back here,' said Bill, looking around the chamber [cut] 'Haven't seen this place for five years.' [GoF ch. #31 p. 535]

Bill's and Charlie's ages are more problematic. We know that both boys had already left Hogwarts by the time Harry started in September 1991, and that Bill was born in November and Charlie in December. Bill was Head Boy, so we know he stayed on for NEWTs and did the full seven years at Hogwarts. In June 1995, just before the third task of the Triwizard Tournament, he tells Harry that he hasn't seen Hogwarts for five years.

This does not prove that Bill started at Hogwarts in 1983 and finished seventh year in 1990, for there are various reasons why a student might repeat a year, or start late, or visit the school again after completing NEWTs. However, it does tell us he finished school by June 1990. So he started at Hogwarts no more recently than September 1983 (assuming he started normally at age eleven) and was born (since he has a November birthday and should therefore have started at Hogwarts during the year in which he turned twelve) no more recently than 1971.

'I'm going to be expelled!' Ginny wept as Harry helped her awkwardly to her feet. 'I've looked forward to coming to Hogwarts ever since B-Bill came and n-now I'll have to leave and -- w-what'll Mum and Dad say? ' [CoS ch. #17 p. 238]

Ginny Weasley speaks of remembering Bill going to Hogwarts, and wanting to go too. She was born in August 1981, so if she means that she remembers him starting at Hogwarts it's very unlikely that she would remember it, and remember that she understood what was happening at the time, if he started in 1982 when she was only a year old. That would peg Bill's birth to November 1971, unless for some reason he started at Hogwarts when he was older than eleven.

Then again, it's pretty unlikely she would remember it that clearly even if she was two. She probably just means that she remembers Bill going to Hogwarts - not that she remembers his first going there. If Bill was born in e.g. 1970 then he left Hogwarts in summer 1989 when Ginny was not quite eight, so it would still be a memory from the fairly distant past, from the perspective of an eleven-year-old.

If she does mean that she remembers him actually starting at Hogwarts, then he could have been born in 1971 and started in 1983 when she was two, but she'd have to have had a very well-developed memory and understanding for a two-year-old. Or he started late, when she was older - perhaps he'd been ill, or had been at another school - and in that case it tells us nothing about his birth-year. On the whole it seems most likely that she just means "I remember when Bill was attending Hogwarts", so it doesn't bear on whether he was born in 1971 or earlier.

Bill was the oldest Weasley brother. He and the next brother, Charlie, had already left Hogwarts. [CoS ch. #04 p. 40]

We know that Charlie is younger than Bill and older than Percy. In JK Rowling's World Book Day Chat on March 4^th, 2004, she was specifically asked: "How old are Charlie and Bill Weasley in relation to their other siblings?" She replied "Oh dear, maths. Let me think. Bill is two years older than Charlie, who is two years older than Percy." According to Accio Quote! she subsequently revised this on her website to say that Bill is two years older than Charlie who is three years older than Percy, although the link given to the original quote on her website is no longer valid.

Since Charlie was born in December and Percy in August it's a bit problematic to say Charlie is three years older than Percy. It could mean that Charlie was three academic years ahead of Percy, was born in 1972 and starting at Hogwarts in 1984, and that Bill was born in 1970. It could mean Charlie is two years, eight and a bit months older than Percy, that Charlie was born in 1973 and started at Hogwarts in 1985, and that Bill was born in 1971.

'Bill and Charlie have already left -- Bill was Head Boy and Charlie was captain of Quidditch.' [PS ch. #06 p. 75]

'He caught that thing in his hand after a fifty-foot dive,' Professor McGonagall told Wood. 'Didn't even scratch himself. Charlie Weasley couldn't have done it.' [PS ch. #09 p. 113]

'I shall speak to Professor Dumbledore and see if we can't bend the first-year rule. Heaven knows, we need a better team than last year. Flattened in that last match by Slytherin, I couldn't look Severus Snape in the face for weeks ...' [PS ch. #09 p. 113]

'I tell you, we're going to win that Quidditch cup for sure this year,' said Fred. 'We haven't won since Charlie left, but this year's team is going to be brilliant. [PS ch. #09 p. 114]

'We know Oliver's speech by heart,' Fred told Harry, 'we were in the team last year.' [PS ch. #11 p. 136]

'This is our last chance -- my last chance -- to win the Quidditch Cup,' [cut]
'Gryffindor haven't won for seven years now.' [PoA ch. #08 p. 108]

'Seriously,' said Professor McGonagall, and she was actually smiling. 'I daresay you'll need to get the feel of it before Saturday's match, won't you? And Potter -- do try and win, won't you? Or we'll be out of the running for the eighth year in a row, as Professor Snape was kind enough to remind me only last night ...' [PoA ch. #12 p. 184]

The whole of Gryffindor house was obsessed with the coming match. Gryffindor hadn't won the Quidditch Cup since the legendary Charlie Weasley (Ron's second-oldest brother) had been Seeker. [PoA ch. #15; p.221/222]

We have a great deal of rather confusing information about Charlie's Quidditch career at Hogwarts, which may help us to establish his birthdate.

We are told that Charlie was a famously good Gryffindor Seeker, and also Gryffindor Quidditch Captain. In autumn 1991 Fred comments that Gryffindor haven't won "since Charlie left", in the same sentence as a comment about having a chance at the Quidditch Cup this year.

Fred also strongly implies that Oliver Wood was Quidditch Captain the previous year, 1990/91, and in autumn 1991 Minerva McGonagall comments that the previous academic year's team, 1990/91, was very bad. This would seem like an odd thing to say if Charlie was still Captain and he was as good a player as her statement that "Charlie Weasley couldn't have done it" - used, as it is, as a mark of awe at Harry's prowess rather than a criticism of Charlie - suggests, so it confirms that Charlie had ceased to be Captain well before the end of the academic year 1990/91

During academic year 1993/94, Oliver Wood says that Gryffindor haven't won the Quidditch Cup for seven years. It's not entirely clear whether he means "There have been seven clear years during which we didn't win the cup" or "We last won the Cup seven years ago", but a comment by McGonagall about potentially being out of the running for the Cup for the eighth year in a row shows that they haven't won it for seven clear years, and their last win was in 1986.

'At the end of the year, the house with the most points is awarded the House Cup' [PS ch. #07 p. 85]
'I'm holding the House Cup and the Quidditch Cup' [PS ch. #12 p. 155]
If they won their next match, against Hufflepuff, they would overtake Slytherin in the House Championship for the first time in seven years. [PS ch. #13 p. 158]
[cut] 'and fifty points will be taken from Gryffindor.'
'Fifty?' Harry gasped - they would lose the lead, the lead he'd won in the last Quidditch match. [PS ch. #15 p. 178]
It was decked out in the Slytherin colours of green and silver to celebrate Slytherin's winning the House Cup for the seventh year in a row. [PS ch. #17 p. 220]

Against that, we have an apparently flatly contradictory statement in PS, where Harry thinks - in January 1992, because it's early in the term after Christmas - that if they win their next Quidditch match, against Hufflepuff, they will overtake Slytherin in the House Championship for the first time in seven years. That would mean they last won in 1985, and if he's referring to the Quidditch Cup there's no way that can be compatible with what both McGonagall and Wood say in PoA.

However, we know that the House Cup and the Quidditch Cup are two separate entities, and that had Slytherin been allowed to keep their victory in the House Cup that year, it would have been the seventh year in a row that they had won it. We are actually told that wins at Quidditch contribute points towards winning the House Cup - when McGonagall docks points after the escapade with Norbert, we see Harry think that he is losing the points which he had gained at Quidditch. We can surmise, then, that when Harry links a win at Quidditch to a House Championship in which Gryffindor haven't beaten Slytherin for seven years as at 1992, he is referring to the House Cup. So we can discount this statement as evidence for Charlie's dates: all it means is that even though Gryffindor won the Quidditch Cup in 1986, Slytherin won the House Cup.

Altogether, then, we have the following information about Bill and Charlie's dates:

1)	Bill was present at Hogwarts in summer 1990, although we don't definitely know that he was a student at that point.
2)	Bill did NEWTs at Hogwarts, was not present at Hogwarts after summer 1990 (except for the Triwizard Tournament) and was therefore born no more recently than 1971, and started at Hogwarts no more recently than September 1983 (unless he started later than first year).
3)	Ginny was born in August 1981.
4)	Ginny remembers Bill going to Hogwarts, and she understood at the time that that was what was happening. It is not clear however whether she means she remembers him starting there.
>5)	Charlie is two years younger than Bill, so he was born no more recently than 1973 and started Hogwarts no more recently than 1985.
6)	Charlie is either 2 years 8 months or 3 years 8 months older than Percy, who was born in August 1976, so Charlie was born in 1973 or 1972.
7)	Charlie had left Hogwarts by September 1991.
8)	At some point in his school career Charlie was Gryffindor Quidditch Captain.
9)	Charlie was a famously good Seeker.
10)	Gryffindor last won the annual Quidditch Cup in 1986.
11)	The last time Gryffindor won the Quidditch Cup Charlie was Seeker (so Charlie was Seeker by the end of 1986).
12)	The Gryffindor team have not won "since Charlie left" although it is ambiguous what they didn't win and in what sense he left.
13)	Charlie's period of tenure on the team is spoken of as if it was some sort of Golden Age.
14)	The 1990/91 Gryffindor Quidditch team was extremely bad.
15)	The 1990/91 Gryffindor Quidditch team was captained by Oliver Wood for at least part of the year.

How can we make sense of the facts that Charlie was Quidditch Captain, that Charlie was considered to be the exemplar of excellence as a Seeker, that Charlie didn't start at Hogwarts until 1984 at earliest, that Gryffindor haven't won since Charlie in some sense "left" and that the last time Gryffindor won the Quidditch Cup was apparently in 1986?

We're told that they they haven't won the Cup since Charlie was Seeker, rather than since Charlie was Captain, so he may well not have been Captain yet when they last won the Cup. Indeed, it's very unlikely he could have been Captain in second year, and even less so in first year, so the sequence must have been: Charlie becomes Seeker; Gryffindor win the Cup; Charlie becomes Captain.

What did Fred mean, when he said that they hadn't won since Charlie left?

a) They hadn't won the Quidditch Cup since Charlie left school. No, because they last won the Cup in 1986 and we know Charlie was at Hogwarts long after that date. He couldn't have been more than a second year in 1986, it's most unlikely that he was Captain in second year, and we know he did become Gryffindor Captain - so he didn't e.g. suddenly leave in 1986 to go to another school. Ergo, he was at Hogwarts well after the last time Gryffindor won the Cup, so there's no reason why Fred would link Charlie leaving Hogwarts with Gryffindor last winning the Quidditch Cup.

b) They hadn't won the Quidditch Cup since Charlie ceased to Captain. No, because they last won the Cup in 1986, when Charlie couldn't have been more than a second year. It's most unlikely that he was already Captain in second year, so his Captaincy happened later and was a separate thing from winning the Cup. So there's no reason why Fred would link Charlie ceasing to be Captain with Gryffindor last winning the Quidditch Cup.

c) They hadn't won the Quidditch Cup since Charlie ceased to be Seeker. Possible but unlikely. We know Charlie was Seeker when they last won the Cup, and he could have suffered an injury or a growth-spurt which forced him to resign as Seeker soon afterwards. But since he went on to captain the team it's unlikely that Fred would characterise his ceasing to be Seeker as his having "left".

d) They hadn't won any matches at all since Charlie left school. Not if Charlie did the full seven years at Hogwarts, because the earliest he could have been born was 1972, which would leave him attending Hogwarts from 1984 to 1991. If Charlie only left Hogwarts in June 1991 it would make no sense for Fred to say, in September 1991, that they hadn't won any matches since Charlie left school. They haven't had a chance to play any matches since Charlie left school. However, it makes perfect sense if Charlie left school earlier than seventh year/1991. If he left school after OWLs, or at the end of sixth year (if he was born in 1972), Gryffindor could perfectly well have won no matches since.

e) They hadn't won any matches at all since Charlie ceased to Captain. Possible, but it would require him to have resigned as Captain before the end of his seventh year, which could not have been earlier than 1990/91. So if he was still at school, he would have sat on the sidelines and watched the disaster which was the 1990/91 Gryffindor team, and not intervened.

f) They hadn't won any matches at all since Charlie ceased to be Seeker. Possible but unhelpful. We know Oliver Wood was Captain in 1990/91, so Charlie had either left school or resigned as Captain. That he might have resigned as Seeker at the same time as ceasing to be Captain tells us nothing extra. And if he ceased to be Seeker at some point before he ceased to be Captain, Fred would be unlikely to see that as him "leaving".

Of these, d) (always assuming that Charlie left school prior to seventh year) and e) are the only ones that work. The idea that Gryffindor hadn't won any matches for a year or even two years would explain why McGonagall was desperate enough to bend the rules to allow a first year to join the team, and to own his own broom....

[cut] this would probably be the best Christmas he'd ever had. Ron and his brothers were staying too, because Mr and Mrs Weasley were going to Romania to visit Charlie. [PS ch. #12 p. 144]

'[cut] you can't tame dragons, it's dangerous. You should see the burns Charlie's got off wild ones in Romania.' [PS ch. #12 p. 169]

We do have another hint that Charlie left Hogwarts itself, not just the Gryffindor Quidditch team, earlier than 1991. At or just after Easter 1992 Ron tells Harry 'You should see the burns Charlie's got off wild [dragons] in Romania.' Ron did not go home at Christmas or Easter that year, so unless he has been fire-calling Charlie without Harry's knowledge, he has to be referring to burns which he has seen on Charlie prior to September 1991. It's possible that Charlie had been doing summer work with dragons for some years before he left school, or that he left school in June 1991 and started work with dragons immediately, so that he had already managed to accumulate some impressive scars only two months later. But it certainly does sound more as if Charlie had been working with dragons for some considerable time before Ron started at Hogwarts, and that would make sense if he left school after OWLs.

Having Charlie leave after OWLs also explains why he didn't become Head Boy, despite being both a prefect and a Quidditch Captain - although of course that may also be true of whoever did become Head Boy.

It is worth noting, incidentally, that it is common and acceptable for British pupils to leave school at sixteen. I went to a grammar school - i.e., a school whose pupils had been selected on the basis of high academic potential - in the 1970s. A high proportion of the students were Jewish or Asian - that is, from cultures which emphasize the importance of education. We had an excellent academic reputation all round. And even so, only about a third of students stayed on after sixteen. It is ridiculous, therefore, to expect that among the Hogwarts students we know of, there wouldn't be some who left after OWLs.

The following scenarios fit everything we've been told:

A: Bill was born in 1971, started at Hogwarts in 1983 and left in 1990.

Charlie was born in 1973 and is two years, eight and a half months older than Percy (which is the closest he can be to being three calendar years older, given their respective birthdays), and two academic years ahead of him. If Charlie had done the full seven years at Hogwarts his years would have been 1985/92, but he in fact left after OWLs in 1990.

Like Harry, Charlie became Seeker when only a first year. However, it remains true that Harry was the youngest Seeker for a century, because he was only eleven when he joined the team, whereas Charlie with his December birthday would probably have been twelve.

Gryffindor last won the annual Quidditch Cup in 1986, when Charlie was a Seeker and was in his first year. Charlie didn't become Captain until after that last win, and although he was an excellent Seeker the rest of the team was not so good, or the other sides were better, and Gryffindor never won the Quidditch Cup during Charlie's term as Captain. Charlie left Hogwarts in 1990, following his OWLs, and Gryffindor won no matches during the single academic year 1990/91.

B: Bill was born in 1970. If he attended Hogwarts from age eleven to eighteen in the normal way he was there from 1982 to 1989, in which case he must have visited the school in summer 1990 for some other reason. Or he might have started a year late or had to repeat a year, perhaps due to illness or injury, and sat NEWTs in 1990.

Charlie was born in 1972 and is three years, eight and a half months older than Percy, and three academic years ahead of him. If Charlie had done the full seven years at Hogwarts his years would have been 1984/91, but he in fact left either after OWLs in 1989, or at the end of his sixth year in 1990.

Gryffindor last won the annual Quidditch Cup in 1986 when Charlie was Seeker and was in his second year: it is unlikely that he could have been already Quidditch Captain and have led his team to victory, but he certainly became Captain later. However, Gryffindor did not win the Cup again during Charlie's term of office. If he left Hogwarts in 1989, Gryffindor won no matches during the two academic years 1989/90 and 1990/91; if he left in 1990, they won no matches during 1990/91.

'Seeker?' [Ron] said. 'But first years never -- you must be the youngest house player in about --' [QTtA ch. #06 p. 28]

Against version A), we have Ron's surprise when Harry is made Seeker, and his statement that "first years never --", which is anomalous if Charlie was Seeker in first year. If Charlie was a first year Seeker he must have been appointed very late in the year, and perhaps only by default after an existing Seeker was injured, for Ron to be so surprised by Harry's appointment.

On the other hand version B), in which Charlie became Seeker in second year, requires us to accept that Bill either stayed at Hogwarts until he was nineteen or re-visited it a year after his NEWTs. It also means that either Gryffindor didn't win any matches at all for two years running, 1989/90 and 1990/91, or Charlie in fact didn't leave until the end of his sixth year.

Since both scenarios require Charlie to have left school before NEWTs, the first is much tidier so long as we can accept another first-year Seeker. It does not result in any need to work round the fact that Bill was last at the school in 1990, and it only requires Gryffindor to have failed to win any matches at all for a single year, not two. However, the fact that nobody ever says to Harry "Charlie was a Seeker in first year too" leads me to conclude, reluctantly, that B) is the more likely scenario. Rowling's website apparently now also gives Bill's birth-year as 1970, although this can't be taken as absolute gospel because she managed to get the date of Dumbledore's death out by a year on the website.

That leaves us with Bill being present at the school in summer 1990, when he was nineteen. He could have been visiting, or been called in as a Curse-Breaker to investigate the curse on the Defence Against the Dark Arts post. He could have done an extra year at Hogwarts: perhaps he missed a year due to illness or injury. Or perhaps for some reason he started a year late, in 1983 when he was twelve, in which case we can if we want have Ginny remembering his first going-away-to-school, so long as she was very well-developed for a two-year-old.

If, in fact, Charlie left school in 1990 at the end of his sixth year, rather than in 1989 after his OWLs, there must have been some sort of crisis, and perhaps Bill came to offer support.

5. In the case of injury, no substitution of players will take place. The team will play on without the injured player. [QTtA ch. #06 p. 28]

Although it is very unlikely that Charlie was Captain in his first or even his second year, since there are no substitutions allowed in Quidditch matches it's possible that the Captain was injured mid-match and Charlie took over, leading his team to victory. An overall win at such a young age would explain his proud reputation, despite the team's failure to win the Cup in subsequent years. And since he does have such a glowing reputation, despite his team never having won the Cup since he was in second year, we must assume that Gryffindor kept losing because their opponents were so good rather than because they were so bad; or perhaps due to circumstances which were none of their fault, such as half the team being struck down with food-poisoning on the morning of an important match.

At any rate, we can conclude that one of two things is true. Either Bill was born in 1971 and Charlie in 1973, and Charlie became Seeker in first year, or Bill was born in 1970 and Charlie in 1972, and Charlie became Seeker in second year. The second option has more support from Rowling. And however you arrange it, Charlie left school before seventh year, so either he didn't do NEWTs at Hogwarts, or he was so brilliant he took them early.

'You're an Auror?' said Harry, impressed. [cut]
'Yeah,' said Tonks, looking proud. 'Kingsley is as well, he's a bit higher up than me, though. I only qualified a year ago.' [OotP ch. #03; p. 52]

'Well, I thought of, maybe, being an Auror,' Harry mumbled.
'You'd need top grades for that,' said Professor McGonagall, extracting a small, dark leaflet from under the mass on her desk and opening it. 'They ask for a minimum of five NEWTs, and nothing under "Exceeds Expectations" grade, I see.' [OotP ch. #29; p. 583]

'Well, you'll need to demonstrate the ability to react well to pressure and so forth,' said Professor McGonagall, 'perseverance and dedication, because Auror training takes a further three years, not to mention very high skills in practical Defence.' [OotP ch. #29; p. 586]

Tonks is someone else whose birth year we can make a good guess at. When she turns up in OotP, in summer 1995, she says that she completed Auror training a year ago, and we know Auror training takes three years. She must have done NEWTs, since the qualifications required to do Auror training are high. So assuming she started training as soon as she left school, and didn't repeat a year anywhere, she attended Hogwarts 1984/1991 (making her an exact contemporary of Charlie Weasley's if he was born in 1972) and was born between September 1972 and August 1973.

Now to the older generation. We know that Snape and the Marauders were in the same academic year, so whatever age they are, so he is. The tombstones we see in Deathly Hallows firmly date James's and Lily's births to early in 1960, so everybody in that year must have been born between September 1959 and August 1960, and they must have attended Hogwarts 1971-1978.

How old is Prof. Dumbledore and Prof. Snape?
JKR: Dumbledore's about 150 years old... Wizards have a longer life expectancy than us Muggles. Snape's 35 or 36 [Red Nose Day Chat, BBC Online, March 12, 2001]

This ties in reasonably well with an online interview given by JK Rowling, after the publication of GoF and whilst she was working on OotP, in which she said that Snape (whose birthday has been established as January 9^th) was thirty-five or thirty-six. If this applies to GoF itself this fits well enough with a 1960 birthdate, which would make him thirty-five at the end of the academic year 1994/95.

He could abandon the plan and simply learn to live with the memory of what his father had done on a summer's day more than twenty years ago ... [OotP ch. #29 p. 588]

In OotP, in the Careers Advice chapter, which takes place in April 1996, Harry thinks that the bullying scene which he saw in the Pensieve took place "more than twenty years ago". The scene took place during OWLs, which are sat in June. That ought to mean that it cannot have occurred in June 1976, or any more recently, because June 1976 is less than twenty years prior to April 1996. That in turn ought to mean that the Marauders started at Hogwarts no more recently than 1970 and we know that's not true. We just have to assume that Harry got it wrong: after all, he may well not know his parents' exact ages.

'All anyone knows is, he turned up in the village where you was all living, on Hallowe'en ten years ago. You was just a year old. He came ter yer house an' -- an' --' [cut]
'You-Know-Who killed 'em. An' then -- an' this is the real myst'ry of the thing -- he tried to kill you, too.' [PS ch. #04; p. 45]

'Black lost everything the night Harry stopped You-Know-Who, and he's had twelve years alone in Azkaban to brood on that ...' [PoA ch. #04; p. 54]

'It was me what rescued Harry from Lily an' James's house after they was killed! Jus' got him outta the ruins, poor little thing, with a great slash across his forehead, an' his parents dead ... an' Sirius Black turns up, on that flyin' motorbike he used ter ride.' [PoA ch. #10; p. 153]

'But he didn't manage to disappear, did he? The Ministry of Magic caught up with him next day!' [PoA ch. #10; p. 153]

'Oh, I know Crouch all right,' he said quietly. 'He was the one who gave the order for me to be sent to Azkaban -- without a trial.' [GoF ch. #27; p. 456]

They reached the bottom of the steps and ran along yet another corridor, which bore a great resemblance to the one that led to Snape's dungeon at Hogwarts, with rough stone walls and torches in brackets. The doors they passed here were heavy wooden ones with iron bolts and keyholes. [OotP ch. #07 p. 124/125]

Rowling also stated on her website that Sirius was about twenty-two when he was sent to Azkaban. In August 1993 Sirius is said to have been in Azkaban for twelve years. This can't quite be true, since it's less than twelve years since the Potters died - but in order for it to have been even nearly true he must have been jailed soon after the murder. We know he was arrested on 1^st or 2^nd November 1981, depending on whether the scene Hagrid describes of Sirius coming to the Potters' house on his flying motorbike - following which he was arrested "next day" - was late on the night of 31^st October or early in the morning of 1^st November. We know that following his arrest he was sent to Azkaban without trial: so allowing for a few days or weeks of interrogation in the cells at the Ministry he presumably arrived at Azkaban by the middle of November.

If he was exactly twenty-two when he was sent to Azkaban that puts his date of birth somewhere between early to mid November 1958 (depending on the exact date he was transferred to Azkaban) and early to mid November 1959 (because he could have been only just twenty-two, or at the other extreme just short of twenty-three).

But in fact he must have been born on or after 1^st September 1959, or he would have ended up in the 1970/77 intake at Hogwarts and that doesn't fit the dating given in Deathly Hallows. So if he really was twenty-two when he entered Azkaban, he was born between early September and mid November 1959. If he was only nearly twenty-two (which would be conssitent with his being "about" twenty-two), then he was born between early September and, say, late December 1959.

STOP PRESS! On 10^th October 2015, Rowling tweeted that Sirius was born on 3^rd November.

'Listen, I knew Bertha Jorkins,' said Sirius grimly. 'She was at Hogwarts when I was, a few years above your dad and me.' [GoF ch. #19; p. 292]

Bertha Jorkins was "a few years" above the Marauders - presumably two or three years.

'Snape knew more curses when he arrived at school than half the kids in seventh year and he was part of a gang of Slytherins who nearly all turned out to be Death Eaters.'
Sirius held up his fingers and began ticking off names. 'Rosier and Wilkes -- they were both killed by Aurors the year before Voldemort fell. The Lestranges -- they're a married couple -- they're in Azkaban.' [GoF ch. #27; p. 460/461]

       'Lestrange ...' Harry said aloud. [cut]
       'They're in Azkaban,' said Sirius shortly. [cut]
       'Bellatrix and her husband Rudolphus came in with Barty Crouch junior,' said Sirius, in the same brusque voice. 'Rodolphus's brother Rabastan was with them, too.' [OotP ch. #06; p. 106]

Sirius tells us in GoF that schoolboy Severus was part of a gang which included a married couple called Lestrange who both ended up in Azkaban, and it certainly sounds as though Sirius means he was at school with this gang, not e.g. meeting them during the holidays. It is possible that this refers to the younger Lestrange brother, Rabastan, and an unnamed wife, but Rowling probably did mean it to refer to Rudolphus and Bellatrix Lestrange.

'No, Andromeda's not on here either, look --'
He pointed to another small round burn mark between two names, Bellatrix and Narcissa. [cut]
[cut] Harry [cut] was too busy staring at the names to the right of Andromeda's burn mark. A double line of gold embroidery linked Narcissa Black with Lucius Malfoy [OotP ch. #06; p. 105]

On the Black family tapestry, as described in OotP, it is clear that Bellatrix is the eldest of the three sisters (she is listed furthest to the left, with Andromeda in the middle and Narcissa on the right). It is likely that the sisters are three separate births, not a pair of twins and one singleton, because twins would normally be written one above the other, not side by side.

'Why aren't you supposed to do magic?'asked Harry.
'Oh, well -- I was at Hogwarts meself but I -- er -- got expelled, ter tell yeh the truth. In me third year. They snapped me wand in half an' everything.' [PS ch. #04; p. 48]

Harry had had reason to believe before now that this umbrella was not all it looked; in fact, he had the strong impression that Hagrid's old school wand was concealed inside it. Hagrid wasn't supposed to use magic. He had been expelled from Hogwarts in his third year, [CoS ch. #07; p. 90]

We know that Nymphadora Tonks, Andromeda's daughter, was born no later than August 1973. Assuming Andromeda left at the end of a school year in the usual manner, and that she wasn't already a mother or very heavily pregnant while at school, she must have left Hogwarts no later than summer 1972 and could only have overlapped Severus and the Marauders at school by a year, if she overlapped them at all. This means that if Andromeda actually stayed the full seven years and took NEWTs (which we don't know, of course), she turned eighteen no later than August 1972 and was born on or before August 1954. If she left school after OWLs she turned sixteen no later than August 1972 and was born on or before August 1956. Any younger than that and we have to assume either that she was heavily pregnant or a mother already whilst still at school, or that she left school before OWLs. In the latter case, judging from Hagrid, she probably wouldn't be allowed to use a wand, and we see no suggestion that this is so. She may of course be older, so long as she is younger than Bellatrix.

If we go solely by what's in the books, then there is no problem about having Bellatrix overlap Severus at school, so long as Andromeda was no more than eighteen in summer 1972. If Andromeda was born in summer 1954, Bellatrix could have been born in autumn 1953 and the two sisters would be in the same academic year, enabling Bellatrix to overlap Severus by a year. If Andromeda was born as late as summer 1956, Bellatrix could have been born anywhere between autumn 1953 and autumn 1955, and overlapped Severus by between one and three years, without any problems.

The only fly in the ointment is that in January 2006 an auction was held to raise money for a charity, and JK Rowling donated a hand-drawn family tree which purported to be the same one as is on the Black family tapestry. There are numerous problems with this family tree, the first and simplest being that all versions of its content have been derived from rather fuzzy images of the original, and Rowling's handwriting is a bit hard to read at the best of times.

Then, assuming the content to have been transcribed properly, there are several problems with the dates. It has two or three people fathering children when they themselves were about thirteen; it has what appear to be James Potter's parents having him when his mother was forty, and dying in late middle-age, when Rowling has said elsewhere that they had James when they were old even by wizarding standards; it has Sirius's mother dying at sixty although her portrait shows an old woman; and it has Regulus dying in 1979 when we were told in OotP that he died in 1980 ("some fifteen years previously" from the viewpoint of August 1995), although the last point can be reconciled by assuming that Regulus died on or just before New Year's Eve and his family initially assumed he had died some days later.

It also shows Bellatrix as having a 1951 birthdate, which on the face of it ought to mean she started at Hogwarts no later than September 1963 and left in June 1970, a whole year before the Marauders and Snape started. And if we want her to be in the same academic year as Molly (and Bill to have been born in 1970) she would have been born earlier in 1951 and have attended Hogwarts from 1962-1969.

It's possible of course just to say "The family-tree is full of errors and it's not in the books, so it's not actually canon", and ignore it. If so, we can happily have Bellatrix and Severus overlapping at Hogwarts by up to three years, as above.

However, the other anomalies do all have possible explanations. Perhaps Walburga Black looked much older than her years because her skin had been wrecked by a drink problem (it would explain a lot about her). The Potters shown in the family tree might be an uncle and aunt of James's, rather than his parents, or the father might have been much older than the mother. It's not unknown for boys to father children at thirteen, and there's a possible reason for the anomaly to do with Regulus as well, of which more anon.

It is possible to accommodate Bellatrix's anomalous birthdate as well, in one of two main ways. The first is just to say that she never did overlap Severus at school, and that the Lestranges he was at school with were Rabastan and an unspecified future wife who also became a Death Eater and also ended up in Azkaban (although she wasn't one of the group tried with Rabastan for the attack on the Longbottoms).

The second is to say that for some reason Bellatrix remained at Hogwarts until 1972, when she would have been twenty, thus enabling her to be born in late 1951 and still overlap Severus by a year. [We don't want her to have been born earlier than September 1951, because that would exacerbate the problem by making her another academic year above Severus.] This could happen because she had to repeat two years, due either to academic failure or to poor health - in her case, probably poor mental health.

[cut] she seemed to be speaking particularly to the Slytherin Captain, Marcus Flint, a sixth-year. [PS ch. #11; p. 136]
Lying in a crumpled heap on the ground were Malfoy, Crabbe, Goyle and Marcus Flint, the Slytherin team captain [PoA ch. 13; p. 194]
Q: In the first book you said Slytherin house Quidditch captain was sixth year Marcus Flint. If there are only seven years of Hogwarts, why is he in the third book?
A. He had to do a year again! :-) [Online chat transcript, Scholastic.com, 3 February 2000]

We know it's possible to repeat at least one year because Rowling has stated that Marcus Flint repeated a year - perhaps due to having been hospitalized with a Quidditch injury, as he is not mentioned during Harry's second year any later than partway through the autumn term. Even though this was really just a fudge which JK introduced to cover the fact that when she wrote about Flint during Harry's third year she outright forgot that she'd said he was in sixth year when Harry was in first, it's a legitimate, JK-sanctioned fudge which can be used to cover for a similar error in dating Bellatrix.

'Who wants to be in Slytherin? I think I'd leave, wouldn't you?' James asked the boy lounging on the seats opposite him, and with a jolt, Harry realised that it was Sirius. Sirius did not smile.
'My whole family have been in Slytherin,' he said. [DH ch. #33; p. 538/539]

Alternatively, Bellatrix could have left school after her OWLs in 1968, perhaps to get married, to have a baby or to join the early Death Eaters, and then changed her mind later (possibly on the Dark Lord's orders) and decided to come back and do NEWTs. We know she was a Slytherin because all the Blacks except Sirius were, and we know Slughorn was teaching at that time, and probably head of house, because his tenure spanned both Tom Riddle before Bellatrix and Severus and Lily after her. Since she was from what seems to be an influential family he probably wouldn't have made any bones about her coming back, if indeed he ever would have done. Depending on how much later she returned, we can theoretically then have her overlap Severus by as much as we like: however, the longer she stayed away from school the less likely it is that she would have returned, so the most probable scenario is that she was away for two years and overlapped Severus by one year.

We can definitely say that whether the tapestry birthdate for Bellatrix is accurate or not she is considerably older than Severus, since Severus was born in January 1960, and Bellatrix has to have been born between autumn 1951 (if we accept the Black family tree as canon) and autumn 1955 (if we go solely by the books).

According to the Black family tree Narcissa, the youngest sister, was born in 1955. This is possible if we assume Andromeda was born no later than March 1955. If we accept the family-tree dates for both Bellatrix and Narcissa we have Bellatrix born in late 1951 (and probably leaving school after OWLs in 1968 and then returning later to take NEWTs from 1970-1972); Andromeda born some time between mid 1952 and early 1955 and Narcissa born in 1955 (and at least nine months after Andromeda, unless she was premature).

I suspect Narcissa has an April birthday, for the simple reason that if this white-blonde baby girl was born when the white-blonde bells of the narcissi were in flower, it might explain why she was given a flower name, instead of a star or constellation name like her sisters and most of the other Blacks.

Sirius jabbed a finger at the very bottom of the tree, at the name 'Regulus Black.' A date of death (some fifteen years previously) followed the date of birth.
'He was younger than me,' said Sirius [OotP ch. #06; p. 104]

We know from OotP that Regulus Black was younger than his brother Sirius, who we know was born in autumn 1959. We also know that he died "some fifteen years" prior to August 1995. Since Harry was more than half way through 1995 when he was thinking about Regulus's date of death, and since subtracting fifteen from ninety-five is such an exceptionally simple and obvious calculation, it is pretty clear from the book that the tapestry shows Regulus as having died in 1980 - if it said 1979 or 1981 one would expect Harry to think "just over/under fifteen years previously".

[cut] when he was sixteen years old, Master Regulus joined the Dark Lord. [cut]
'And one day, a year after he had joined, master Regulus came down to the kitchen to see Kreacher. [cut]
'... he said that the Dark Lord required an elf.' [DH ch. #10; p. 159]

'So what happened when you got back?' Harry asked. [cut]
[cut] '... a little while later ... Master Regulus came to find Kreacher in his cupboard one night [cut] and he asked Kreacher to take him to the cave, the cave where Kreacher had gone with the Dark Lord ...' [DH ch. #10; p. 161]

We know from Kreacher that Regulus joined the Dark Lord when he was sixteen, that the locket Horcrux was placed in the bowl "a year after he had joined" and that Regulus died "a little while later". That doesn't necessarily mean the first cave incident was exactly a year afterwards, but I think we can assume fairly safely that it was not less than nine months or more than fifteen months later, or Kreacher would have rounded it to six or eighteen months. That means that Regulus's age at death was somewhere between just under seventeen (if he joined just after his sixteenth birthday and died just before his seventeenth) and just over eighteen (if he joined just before his seventeenth birthday and died soon after his eighteenth).

The Black family tree which Rowling donated to a charity auction - and which is supposedly a copy of the Black tapestry in OotP - gives Regulus's dates as 1961-1979, which doesn't match what we're told in the books, and book canon takes precedence. One doesn't know whether to make it 1961-1980, or shift the whole thing forward a year and say 1962-1980. It does however definitely show that Rowling intends Regulus to have been seventeen or eighteen when he died, not sixteen.

'Was he killed by an Auror?' Harry asked tentatively.
'Oh, no,' said Sirius. 'No, he was murdered by Voldemort. Or on Voldemort's orders, more likely; I doubt Regulus was ever important enough to be killed by Voldemort in person. From what I found out after he died, he got in so far, then panicked about what he was being asked to do and tried to back out. Well, you don't just hand in your resignation to Voldemort. It's a lifetime of service or death.' [OotP ch. #06; p. 104]

       [cut] '... a little while later ... Master Regulus came to find Kreacher in his cupboard one night [cut] and he asked Kreacher to take him to the cave, the cave where Kreacher had gone with the Dark Lord ...' [cut]
       'And he ordered -- Kreacher to leave -- without him. And he told Kreacher -- to go home -- and never to tell my mistress -- what he had done -- but to destroy -- the first locket. And he drank -- all the potion -- and Kreacher swapped the lockets -- and watched ... as Master Regulus ... was dragged beneath the water ... and ...' [cut]
       [cut]'And his mistress was mad with grief, because Master Regulus had disappeared, and Kreacher could not tell her what had happened, no, because Master Regulus had f -- f -- forbidden him to tell any of the f -- f -- family what happened in the c -- cave ...' [DH ch. #10; p. 161-163]

There is actually a way to reconcile the two dates, however. We know that Regulus's family didn't actually know how he died. If we assume that he died only a day or two before the New Year of 1980, it might well be that his family initially guessed that he had gone on the run and had been killed days or weeks after they last saw him, and therefore listed his death as occurring in 1980, after the New Year. After Vold War Two, when Kreacher finally told the true story of Regulus's death and he became known as a hero in the fight against Voldemort, the surviving Blacks - Andromeda and Narcissa - updated the tapestry to state correctly that Regulus died in 1979.

That would mean that Regulus was born late in 1961 - most likely in November or December - and was just over eighteen when he died. That in turn would mean that he was still at school, assuming he stayed on for NEWTs: Sirius doesn't say so, but there's no particular reason why he should. Sirius on the whole seems to approve of Harry being in the Order, so he's not going to say that it's shocking that a schoolboy who was well of-age was involved in the war; but at the same time he's fairly sensible about danger as it applies to Harry, and probably wouldn't want to actually encourage him to take stupid risks either. Better to let "He was still at school" pass unsaid.

If we ignore the charity version of the tapestry and likely authorial intent, and go solely by the book, the earliest Regulus could have died was the end of 1979 and the oldest he could have been when he died was say 18 and 3 months, so the earliest he could have been born was September/October 1961. The latest he could have died was late 1980, and the youngest he could have been was not quite 17, so the most recent date he could have been born was very early in 1964.

'The company you keep, Weasley ... and I thought your family could sink no lower --'
There was a thud of metal as Ginny's cauldron went flying; Mr Weasley had thrown himself at Mr Malfoy, knocking him backwards into a bookshelf. [CoS ch. #04; p. 51]

"I fell much easier in my mind now that I know Dumbledore is being subjected to fair and objective evaluation," said Mr Lucius Malfoy, 41 [OotP ch. #15; p. 275]

'Tell me, how is Lucius Malfoy these days? I expect he's delighted his lapdog's working at Hogwarts, isn't he?' [OotP ch. #24; p. 460]

'Slytherin!' cried the Sorting Hat.
And Severus Snape moved off to the other side of the Hall [cut] to where Lucius Malfoy, a prefect badge gleaming upon his chest, patted Snape on the back as he sat down beside him ... [DH ch. #33; p. 540]

According to the Daily Prophet, which may or may not have got it right, Lucius Malfoy was forty-one when he was mentioned in an article which appeared at some point in mid September 1995: so he was born some time between mid September 1953 and mid September 1954, and probably started at Hogwarts in 1965 and left in 1972 - unless he was born in early September 1954, in which case he would have attended Hogwarts from 1966 to 1973. The longest Lucius and Snape could have overlapped for at school would have been two years, and that only if Lucius was born in early September 1954.

We also know that Lucius was a prefect in Severus's first year, so he had to have been a fifth year at least. This corroborates the Prophet's evidence that he was a sixth or seventh year when Severus was a first year. We do not actually know whether there are any seventh-year prefects, or whether the fact that Lucius was a prefect means he has to have been a sixth year.

The fact that Sirius calls young Snape Lucius's "lapdog" argues in favour of their having known each other for a fairly long time at school, which would put Lucius's birthday in early September 1954. However, the fact that he knows and detests Arthur Weasley (who, as I shall show, was born no later than 1952) well enough to brawl with him in public argues in favour of making Lucius as old as he can be, so his exact birth year remains an open question.

'Now ... how long have you been teaching at Hogwarts?' she asked, her quill poised over her clipboard.
'Fourteen years,' Snape replied. [OotP ch. #17; p. 323]

We know incidentally from what he tells Umbridge in autumn 1995 that Snape started teaching at Hogwarts in 1981 (just before Harry's parents were killed). The horrible incident after the OWLs occurred when he was sixteen. It is ambiguous in the book whether the audience for that nasty bit of humiliation consisted only of students who had just come out from OWL and NEWT exams or whether the junior years were also around - but since exams in British schools tend to finish at lunchtime it is quite likely that pupils of all ages witnessed the incident.

If Snape was born in 1960, which seems definite given what we're told in Deathly Hallows, then he started teaching when he was twenty-one (we don't know if he was made Head of House at that age, but presumably the fact that Snape became Potions master means Slughorn had retired). In his first teaching-year, the fifth, sixth and seventh-year students had all been already at Hogwarts when he was a student, and presumably knew him as Snivellus, the bullies' favourite victim. That is, the students who were in first, second and third years during Snape's seventh year in 1977/78 would be respectively in fifth, sixth and seventh years in academic year 1981/82.

Worse, the students who were seventh years in 1981/82 had been first years in 1975/76, the year of Snape's OWLs. That means that when he joined the staff he was teaching a seventh-year class who not only were not much younger than himself, but who had (at least potentially) witnessed him being stripped and hung upside-down. It's not surprising he developed a hostile, defensive attitude to his students.

'They planted the Whomping Willow the same year that I arrived at Hogwarts.' [PoA ch. #10; p. 139]

'I told you, months ago, that the Whomping Willow was planted the year I came to Hogwarts. The truth is that it was planted because I had come to Hogwarts. This house --' Lupin looked miserably around the room, '-- the tunnel that leads to it -- they were built for my use. Once a month, I was smuggled out of the castle, into this place, to transform. The tree was placed at the tunnel mouth to stop anyone coming across me while I was dangerous.' [PoA ch. #18; p. 258/259]

Mrs Weasley was intrigued by the Whomping Willow, which had been planted after she had left school [GoF ch. #31 p. 536]

'We danced to this when we were eighteen!' said Mrs Weasley, wiping her eyes on her knitting. 'Do you remember, Arthur?' [HBP ch. #16; p. 310]

We know that Molly Weasley (née Prewett) left Hogwarts before the Whomping Willow was planted, and that the Whomping Willow was planted during the Marauders' first year - or perhaps even just before they started, since it was a safety-measure to keep people away from Remus while he was transformed. Assuming that Molly left as normal at the end of an academic year rather than partway through a year, she must therefore have left school before Snape and the Marauders started. So she must have left school no later than summer 1971. She has an October birthday so she started Hogwarts in the year in which she would later turn twelve, and assuming that she stayed on for NEWTs she must have been born no more recently than 1952, and started at Hogwarts no more recently than 1964.

However, Bill Weasley was born no more recently than November 1971, so unless Molly was four months pregnant when she finished school, we can assume she left no later than 1970, a year before Snape and co. started - or earlier of course. If Bill was born in 1970, which is the more likely option, she left no later than 1969, and was born no more recently than 1950.

We do not know whether Arthur Weasley was in the same academic year as Molly or not, but Molly says they danced together when they were both eighteen. Given that Molly has an October birthday and Arthur a February one, in order for them to have been eighteen (or indeed any age) simultaneously Arthur must be either four months younger or eight months older than Molly, and he must have been either in the same academic year as her or in the year above her.

'Gideon Prewett, it took five Death Eaters to kill him and his brother Fabian, they fought like heroes' [OotP ch. #09; p. 158]

Although Molly did not overlap with Snape and the Marauders, her brothers may have done. JK has confirmed on her website that Gideon and Fabian Prewett were Molly's brothers but we don't know whether they were older or younger than her (or even twinned or tripletted with her): only that they were old enough that when they were killed, during the height of Vold War One, Gideon was an Order member (he's in the Order group photo' which Moody shows to Harry) and both fought valiantly.

'You can't blame them,' said Dumbledore gently. 'We've had precious little to celebrate for eleven years.' [PS ch. #01; p. 13]

       'What were you doing out of your dormitory at four in the morning?' said Bill, surveying his mother with amazement.
       Mrs Weasley grinned, her eyes twinkling.
       'Your father and I had been for a night-time stroll,' she said. 'He got caught by Apollyon Pringle -- he was the caretaker in those days -- your father's still got the marks.' [GoF ch. #31; p. 535]

[cut] 'we happen to be talking about one of the most powerful wizards of all time, a wizard who has eluded capture for almost three decades!' [HBP ch. #01; p. 18]

'It was the same last time he was powerful, people eloping left right and centre -'
'Including you and Dad,' said Ginny slyly.
'Yes, well, your father and I were made for each other, what was the point in waiting?' [HBP ch. #05; p. 92]

We do not know how old Molly and Arthur were when Bill was born. However, we know that they eloped together (and presumably married) at a time when Voldemort was powerful, and we have references which suggest Voldemort only became a real threat in about 1970. In 1981, Dumbledore says that the British wizarding world has had little to celebrate for eleven years - that is, since 1970 - and in 1996 Fudge tells the Muggle Prime Minister that Voldemort has been eluding capture for almost thirty years. Unless Bill (who was born no more recently than 1971) was born before his parents' marriage, Molly and Arthur must have eloped prior to winter 1971, and no earlier than the late 1960s at earliest, since it was at a time when Voldemort was already an obvious threat.

Since Bill was born in either 1970 or 1971, this suggests that they may well have eloped because Molly was pregnant. Since we know they were already courting at school, it seems highly likely that the elopement took place not long after they finished at Hogwarts (in fact Molly actually says there was no point in waiting), and that they are about as young as they can be and still fit in with Molly having left school by summer 1970/71, and Bill being born in November 1970/71. If we assume Molly didn't get pregnant until after she left Hogwarts (which is a big if) she was probably born in 1950/51, and Arthur in 1950/51 or 1951/52.

The fact that Arthur and Lucius Malfoy still have such a fierce rivalry that they are willing to throw away all dignity and brawl in public as adults suggests they probably knew and hated each other at school. Since Lucius was born no earlier than September 1953 (but more probably in September 1954), this also argues in favour of Arthur being as young as he could be, i.e. born in 1951 or 1952, to reduce the number of academic years between himself and Lucius to a minimum. This has the added benefit of placing Arthur in the same academic year as Molly. That then also constrains Molly to having been born in 1950 or 1951.

If, in fact, Molly left school after OWLs, pregnant, making her the youngest she could possibly be, then we can move everybody's ages up three years and have Molly born in 1953 or 1954 and Arthur in 1954 or 1955, which could potentially place Arthur and Lucius in the same academic year.

Hagrid wasn't supposed to use magic. He had been expelled from Hogwarts in his third year, but Harry had never found out why [CoS ch. #07; p. 90]

'And father won't tell me anything about the last time the Chamber was opened, either. Of course, it was fifty years ago, so it was before his time' [CoS ch. #12; p. 167]

Harry saw at once that it was a diary, and the faded year on the cover told him it was fifty years old. He opened it eagerly. On the first page he could just make out the name 'T. M. Riddle' in smudged ink.
'Hang on,' said Ron, who had approached cautiously and was looking over Harry's shoulder, 'I know that name ... T. M. Riddle got an award for special services to the school fifty years ago.' [CoS ch. #13; p. 172/73]

'Of course I know about the Chamber of Secrets. In my day, they told us it was a legend, that it did not exist. But this was a lie. In my fifth year, the Chamber was opened and the monster attacked several students, finally killing one. I caught the person who'd opened the Chamber and he was expelled. [CoS ch. #13; p. 180]

'It was Hagrid, Ron. Hagrid opened the Chamber of Secrets fifty years ago.' [CoS ch. #13; p. 184]

We know that the Chamber of Secrets was opened fifty years ago, from the perspective of academic year 1992/93, so in 1942/43: and we know that during that year Tom Riddle was in fifth year. We know that Hagrid was expelled during that year and that Hagrid was expelled during his third year, ergo Hagrid was in third year when Tom was in fifth. So Tom was born on New Year's Eve 1926 and attended Hogwarts 1938/1945, and Hagrid was born in December 1928 and attended Hogwarts 1940/1943.

Dumbledore is a hundred and fifty, and Professor McGonagall is a sprightly seventy. Wizards have a much longer life expectancy than Muggles. [Live interview on Scholastic.com on October 16, 2000]

'She was transferred to St Mungo's this morning. Four Stunning Spells straight to the chest at her age? It's a wonder they didn't kill her.' [OotP ch. #32; p. 644]

Regarding the age of Minerva McGonagall, we have no direct evidence in the books except that she is not young. In an online interview given after the publication of GoF and while working on OotP, JK Rowling said that Minerva was seventy. If we take this as accurate and exact, she was born in October 1924, making her around two years older than Tom, and she attended Hogwarts 1936/1943. However, assuming that she did a full seven years, the fact that she does not seem to have much input to offer on either Tom or the Chamber of Secrets may mean that JK's stated age for her was only approximate and that she was three years ahead of Tom and left before the Chamber was opened. That would mean she was born in 1923 and attended Hogwarts 1935/1942.

Upon graduation from Hogwarts, Minerva returned to the manse to enjoy one last summer with her family before setting out for London, where she had been offered a position at the Ministry of Magic [cut] it was then, aged only eighteen, that she proved herself truly her mother’s daughter, by falling head-over-heels in love with a Muggle boy. [cut]
       Finally, after two years at the Ministry, [cut] She sent an owl to Hogwarts, asking whether she might be considered for a teaching post. The owl returned within hours, offering her a job in the Transfiguration department, under Head of Department, Albus Dumbledore. [Pottermore website]
       'How long have you been teaching at Hogwarts?' Professor Umbridge asked.
       'Thirty-nine years this December,' said Professor McGonagall brusquely [OotP ch. #15; p. 287]

New post-book information introduced on Pottermore, however, indicates that Minerva started working for the Ministry when she was eighteen and had only been working there for two years when she started teaching at Hogwarts, which we know occurred in December 1956 (because in September 1995 she tells Umbridge she's been there thirty-nine years come December). If we accept Pottermore as canon, and assuming her two years at the Ministry were continuous, and that the figure of two years is accurate, this gives her a birthdate in October 1935, and she would have been a student 1947/1954, missing Tom by two years.

Minerva's school career overlapped by two years with that of Pomona Sprout, later Head of Hufflepuff House, [Pottermore website]

Tiny little Professor Flitwick, the Charms teacher, was sitting on a large pile of cushions beside Professor Sprout, the Herbology teacher, whose hat was askew over her flyaway grey hair. [GoF ch. #12; p. 155]

The door swung open at once. A tall, black-haired witch in emerald-green robes stood there. [cut]
'The firs'-years, Professor McGonagall,' said Hagrid. [PS ch. #07; p. 85]

According to Pottermore Pomona Sprout and Minerva MacGonagall overlapped each other at school by two years, so Pomona is either five years older or five years younger than Minerva. As she has grey hair and Minerva has black, she's probably the elder, so she would have been a student 1942/1949 and born in May 1931.

Dumbledore is a hundred and fifty, and Professor McGonagall is a sprightly seventy. Wizards have a much longer life expectancy than Muggles. [Live interview on Scholastic.com on October 16, 2000]

George Moore for The Times - How old is Dumbledore?
JK Rowling: I see him as about 150 [Edinburgh "cub reporter" press conference, ITV, 16 July 2005]

As for Albus Dumbledore, Rowling has three times stated in interviews that he is about a hundred and fifty, but the textual evidence in Deathly Hallows does not support this.

[cut] Albus had arrived at Hogwarts under the burden of unwanted notoriety. Scarcely a year previously, his father, Percival, had been convicted of a savage and well-publicised attack upon three young Muggles. [DH ch. #02; p. 21]

Three years after we had started at Hogwarts Albus's brother, Aberforth, arrived at school. [DH ch. #02; p. 22]

When Albus and I left Hogwarts , we intended to take the then traditional tour of the world together [cut] On the very eve of our trip, Albus's mother, Kendra, died, [DH ch. #02; p. 23]

'You there! Give me your chair, I'm a hundred and seven!' [DH ch. #08; p. 128]

[cut] 'those of us who were alive then never knew what really happened.' [cut]
[cut] 'Why did half of us never even know she existed, until they carried the coffin out of the house and held a funeral for her?' [DH ch. #08; p. 129]

'Bathilda described the whole thing to Mother while I was listening at the door. A coffin-side brawl!' [DH ch. #08; p. 131]

The baby, Ariana, was little longer than a loaf of bread and no more distinctive-looking. [cut] Albus and Aberforth wore matching lacy collared jackets and had identical, shoulder-length hairstyles. Albus looked several years older, but otherwise the two boys looked very alike, [DH ch. #11; p. 178]

'When my sister was six years old, she was attacked, set upon, by three Muggle boys.' [DH ch. #28; p. 454]

Barely two months into their great new friendship, Dumbledore and Grindelwald parted [DH ch. #18; p. 292]

'Then, when she was fourteen [cut] She had one of her rages and [cut] it was an accident. Ariana couldn't control it. But my mother was killed.' [DH ch. #28; p. 455/456]

'So that put paid to Albus's trip round the world with little Doge. The pair of 'em came home for my mother's funeral and then [cut] Albus settled down as head of the family.' [cut]
'I'd have looked after her, I told him so, I didn't care about school, I'd have stayed home and done it. He told me I had to finish my education [cut] But he did all right for a few weeks ... 'til he came.' [DH ch. #28; p. 456]

'But after a few weeks of it, I'd had enough, I had. It was nearly time for me to go back to Hogwarts' [cut] it took little imagination to see him as a teenager, wiry and angry, confronting his elder brother. [DH ch. #28; p. 456]

[cut] 'I don't know which of us did it, it could have been any of us -- and she was dead.' [DH ch. #28; p. 457]

We see from the accounts of both Elphias Doge and Aberforth that the death of Albus's mother Kendra occurred just after Albus had finished at Hogwarts (just before he had planned to set off on a world tour with Doge), and Ariana's death happened just before the start of the next Hogwarts term. Albus must have been either seventeen or eighteen at the end of the school year and eighteen at the end of the summer holidays. If he was still seventeen at the end of the summer he would have been a year lower: if nineteen, a year higher.

Now approaching his eighteenth birthday, Dumbledore left Hogwarts in a blaze of glory [DH ch. #18; p. 288]

[cut] I'd sometimes hear an owl tapping at Gellert's bedroom window, delivering a letter from Albus! An idea would have struck him, and he had to let Gellert know immediately!'
And what ideas they were. Profoundly shocking though Albus Dumbledore's fans will find it, here are the thoughts of their seventeen-year-old hero, as relayed to his new best friend (a copy of the original letter may be seen on page 463): [DH ch. #18; p. 291]

According to Rita Skeeter (not the most reliable source) Albus was not quite eighteen when he left Hogwarts. That means he was one of the youngest in his year, like Harry. According to Aberforth he took up with Gellert a few weeks after he left school, and according to Rita he was still seventeen when he wrote to Gellert about "the Greater Good", at which point it sounds as if he'd known him at least for a couple of weeks, since they were obviously well into their political discussions and close enough to exchange night-time owls. If he was nearly eighteen when he left school, met Gellert two weeks later and wrote the letter a few weeks after that, at which point he was still seventeen, his birthday was probably five or six weeks after he left school.

If both Aberforth and Rita are accurate, Albus must have left Hogwarts in mid June as soon as he'd finished his NEWTs, rather than staying to the end of term. We know this because he took up with Grindelwald a few weeks after he left school (according to Aberforth), and split up with him after two months (according to Rita), which was just before the start of the new Hogwarts term (according to Aberforth). That is, he left school about two and a half months prior to the start of the following academic year. If his eighteenth birthday was five or six weeks after he left school, it probably fell in the second half of July.

Ariana was fourteen when Kendra died, so she was around four years younger than Albus - although she could be as little as three years younger if she was nearly fifteen to his nearly-eighteen. She was injured by the Muggle boys when she was six, and her father was convicted of his revenge attack on them almost exactly a year before Albus started at Hogwarts: therefore, when Albus had recently turned ten. If her and Albus's birthdays were very close together, she coud have only just turned six; although the odds are that their birthdays weren't very close together, she was six when Albus had just turned ten and she was also six when he was still nine, and so she was somewhat less than four years younger than him.

Aberforth was three academic years behind Albus. Depending on when their birthdates fell he could be as little as two years plus one day younger than Albus in absolute terms (if Albus was born on 31^st August 1881 and Aberforth on 1^st September 1883). The degree of responsibility which he assumes for Ariana, as well as the fact that Ariana is a babe in arms in their group portrait, whilst Aberforth is old enough to be dressed to match his elder brother, confirms that Aberforth is at least a year older than her. Since she is probably less than four years younger than Albus, Aberforth is less than three years younger than him.

So, Ariana's death occured when Albus was either just eighteen or (if he was born at the end of August) within a few days of eighteen. Auntie Muriel, who is a hundred and seven in summer 1997, must have been born in 1889 or 1890, and she was a child when Ariana died - and an old-enough child that she remembers the events and knows that she was surprized that she hadn't known about Ariana before the funeral.

Say that Muriel was between five and fifteen when Ariana died, that means Ariana died some time between 1894 and 1905. Albus turned eighteen some time between 1893 and 1905, was born between September 1875 and August 1887, and was between a hundred and nine and a hundred and twenty-one when he died. It's probably best to say that Muriel was about ten when Ariana died, which was in about 1900, and Albus was born circa 1882, all give or take about six years. And whenever Albus was born, Aberforth was born two or three years later and Ariana three to four years later.

In the family group portrait, Ariana is a small baby. Aberforth is enough older than her that he is dressed as a little boy rather than as a baby, and Albus is visibly "several years" older than Aberforth. Therefore, we should probably make the age-gap between Ariana and Albus as great as possible, and say that Ariana had only just turned fourteen when Kendra died, so she was about a month less than four years younger than Albus. Aberforth would be about three yours younger than Albus (so he too would be one of the youngest in his year) and a year older than Ariana.

On 1^st September 2007 JK Rowling's website named Dumbledore as wizard of the month and gave his dates as 1881-1996. The 1996 date of death was emphatically wrong, and was later revised to 1997. The Pottermore dating is still off because it gives Dumbledore's date of death as 30^th June and in the book he died just before the start of exams, so around 6^th June (unless you're going with the theory I proposed in Mood Music, in which Dumbledore's apparent death on the Tower was faked but he nevertheless died of the poison a few weeks later). The birth date in 1881 has stayed as is.

Their teacher, Madam Hooch, arrived. She had short, grey hair and yellow eyes like a hawk. [PS ch. #09; p. 109]

Madam Hooch, [cut] gave them the benefit of her professional opinion.
'Look at the balance on it! If the Nimbus series has a fault, it's a slight list to the tail-end -- you often find they develop a drag after a few years. They've updated the handle, too, a bit slimmer than the Cleansweeps, reminds me of the old Silver Arrows -- a pity they've stopped making them, I learned to fly on one, and a very fine old broom it was too ...' [PoA ch. #13; p. 188]

The Moontrimmer, which was first created by Gladys Boothby in 1901, represented a leap forward in broom construction, [cut] Gladys Boothby was unable to produce Moontrimmers in the quantities Quidditch players clamoured for. The production of a new broom, the Silver Arrow, was welcomed; this was the true forerunner of the racing broom; [cut]
The breakthrough occurred in 1926, when the brothers Bob, Bill and Barnaby Ollerton started the Cleansweep Broom Company. [QttA ch. #09; p. 48/49]

When they arrived at Hagrid 's cabin, however, they found an elderly witch with closely cropped grey hair and a very prominent chin standing before his front door. [cut]
'My name is Professor Grubbly-Plank,' she said briskly, [GoF ch. #24; p. 379]

Regarding other staff members, we know that Rolanda Hooch and Wilhemina Grubbly-Plank have grey hair. The Harry Potter Lexicon also points out that Hooch says she learned to fly on a Silver Arrow, which according to Quidditch Through the Ages is a broom which was first made some time between 1901 and 1926 - although if course we don't know how old it was when young!Hooch was learning to fly on it. The fact that she refers to her Silver Arrow - and it does sound as if she is talking about her own broom, and not about the model in general - as "a very fine old broom" may mean that the one she learned on had been around for a long time. Nor do we know how long the Silver Arrow remained in production: Hooch says it's "a pity they've stopped making them", which sounds as if they had been still produced until fairly recently. All we can say with confidence is that Hooch was probably not born before 1890 or after 1950.

Ron's wand was still malfunctioning, surpassing itself on Friday morning by shooting out of Ron's hand in Charms and hitting tiny old Professor Flitwick squarely between the eyes [CoS ch. #07; p. 81]
Professor Flitwick, who was a tiny little wizard with a shock of white hair [PoA ch. #05; p. 71]

Filius Flitwick is described as old, and has white hair. JKR says on her website that he has "a dash of goblin ancestry - something like a great, great, great grandfather", so it's possible he has a greater than human/wizard life-span, and is very old indeed.

'Lily Evans. One of the brightest I ever taught. Vivacious, you know. Charming girl. I used to tell her she ought to have been in my house. Very cheeky answers I used to get back, too.'
       'Which was your house?'
       'I was Head of Slytherin,' said Slughorn. [HBP ch. #04; p. 70/71]
'In the summer of his sixteenth year, he left the orphanage to which he returned annually and set off to find his Gaunt relatives.' [HBP ch. #17; p. 340]
It was a much younger Horace Slughorn. Harry was so used to him bald that he found the sight of Slughorn with thick, shiny, straw-coloured hair quite disconcerting; it looked as though he had had his head thatched, though there was already a shiny Galleon-sized bald patch on his crown. His moustache, less massive than it was these days, was gingery-blond. [cut]
       Harry looked around as Dumbledore appeared beside him and saw that they were standing in Slughorn's office. Half a dozen boys were sitting around Slughorn, [cut] all in their mid-teens. Harry recognised Riddle at once. [cut] His right hand lay negligently upon the arm of his chair; with a jolt, Harry saw that he was wearing Marvolo's gold and black ring; he had already killed his father. [HBP ch. #17; p. 345/346]

Dumbledore say that Tom Riddle killed his father in the summer of his sixteenth year, i.e. when he was fifteen, in summer 1942 (Rowling probably doesn't know the difference between "his sixteenth year" and "the year he was sixteen", and meant the latter, but it's not credible that Dumbledore would make such a glaring error). Horace Slughorn was Head of Slytherin when Lily, Snape etc. were at school. It's not clear whether he was Head of House when Tom was at school or not, but he was already holding either Slug Club sessions or Slytherin meet-ups, as we see Tom and his friends gathered in Horace's office. This is while Tom is still at school but after he killed his father, so between autumn 1942 and summer 1945, and the reference to his being in his mid-teens says 1942 or 1943. Horace is just beginning to go bald so most likely he's in his mid 30s, placing his birth somewhere around 1908.

The very same summer that Dumbledore went home to Godric’s Hollow, now an orphan and head of the family, Bathilda Bagshot agreed to accept into her home her great nephew, Gellert Grindelwald. [DH ch. #18; p. 290]

At sixteen years old, even Durmstrang felt it could no longer turn a blind eye to the twisted experiments of Gellert Grindelwald, and he was expelled.
Hitherto, all that has been known of Grindelwald's next movements is that he 'travelled abroad for some months'. It can now be revealed that Grindelwald chose to visit his great aunt in Godric's Hollow [DH ch. #18; p. 290]

Naturally, I introduced him to poor Albus, who was missing the company of lads his own age. [DH ch. #18; p. 291]

'It was poor little Ariana dying, I think, that did it,' says Bathilda. 'It came as an awful shock. Gellert was there in the house when it happened, and he came back to my house all of a dither, told me he wanted to go home the next day.' [DH ch. #18; p. 292]

Gellert Grindelwald was a little younger than Albus. He was expelled from Durmstrang when he was sixteen, evidently towards the end of an academic year, since we are told he then travelled abroad for "some months", and we know he spent July and August of those months in Godric's Hollow and then supposedly went home. Rita speaks as if he went to visit his great-aunt Bathilda almost immediately, and says that he went there in the summer, so he had not been at Bathilda's house, or expelled, for very long before Albus met him. So he was expelled probably a month or so before Albus finished Hogwarts, circa May 1899 (1900, if Albus was born in 1882), at which point he was sixteen.

He could have been a fifth year who had only recently turned sixteen, or a sixth year who was about to turn seventeen. That is, he could have been as little as one calendar year younger than Albus, or almost two. Since Bathilda reportedly said Albus needed the company of boys his own age, and evidently didn't consider that Aberforth - who was less than three years younger than Albus - qualified, it is likely that Gellert was closer in age to Albus than to Aberforth. That means that when he was expelled he was a sixth year, and rising seventeen. Hence, he too was born in the summer, in 1882 (1883 if Albus was born in 1882).

Harry thought Professor Marchbanks must be the tiny, stooped witch with a face so lined it looked as though it had been draped in cobwebs; [cut]
'I doubt it,' shouted tiny Professor Marchbanks, 'not if Dumbledore doesn't want to be found! I should know ... examined him personally in Transfiguration and Charms when he did NEWTs ... did things with a wand I'd never seen before.' [OotP ch. #31; p. 626/627]

Another character for whom we have a clear indication of age is Griselda Marchbanks. She was an examiner when Albus sat his NEWTs - so we are probably safe to assume she's at least ten years older than him and was born in the early 1870s, or earlier.

Bathilda Bagshot must have been even older than Griselda, since she was Grindelwald's great aunt, welcomed the Dumbledore family to Godric's Hollow as an adult, was apparently already an author when Albus was a teenager, and was friends with Muriel's mother. She was two generations above Albus and Gellert, and even if Gellert's family only had a twenty-year generation time, and Bathilda was fifteen years younger than her sibling who was Gellert's grandparent, she must still have been a good twenty-five years older than Gellert. So she was born probably no more recently than 1857. Enid Smeek was old enough to remember the Dumbledores clearly, and was probably older than Aberforth, since he threw dung at her, and he probably wouldn't have done so to a young girl. Elphias Doge seems to have been in the same academic year as Albus, since they were friends and due to go on tour at the same time.

'My mother was friendly with old Bathilda Bagshot,' said Auntie Muriel happily. [DH ch. #08; p. 131]

Another such easily satisfied friend of the family was Bathilda Bagshot, the celebrated magical historian who has lived in Godric's Hollow for many years. Kendra, of course, had rebuffed Bathilda when she first attempted to welcome the family to the village. Several years later, however, the author sent an owl to Albus at Hogwarts, having been favourably impressed by his paper on Trans-Species Transformation in Transfiguration Today. [DH ch. #18; p. 288]

'He were a headcase, that Aberforth,' says Enid Smeek, whose family lived on the outskirts of Godric's Hollow at that time. 'Ran wild. 'Course, with his mum and dad gone you'd have felt sorry for him, only he kept chucking goat dung at my head.' [DH ch. #18; p. 288]

When Albus and I left Hogwarts, we intended to take the then traditional tour of the world together, visiting and observing foreign wizards, before pursuing our separate careers. [DH ch. #02; p. 23]

At the other end of the scale are the younger generation described in Deathly Hallows and in interview/website canon. Knowing that Harry's second year at school was 1992/93 and that the Battle of Hogwarts took place in the spring of what would have been his seventh year, we can calculate that the war ended in 1998.

But not until March did luck favour Ron at last. [DH ch. #22; p. 355]

'My son, Draco, is home for his Easter holidays. If that is Harry Potter, he will know.' [DH ch. #23; p. 370]

Slowly, the days stretched into weeks. [DH ch. #25; p. 411]

'I'm sorry,' he told Fleur, one blustery April evening [DH ch. #25; p. 412]

Lupin fell over the threshold. He was white-faced, wrapped in a travelling cloak, his greying hair windswept. He straightened up, looked around the room, making sure of who was there, then cried aloud, 'It's a boy! We've named him Ted, after Dora's father!' [DH ch. #25; p. 415]

Teddy Lupin we know was born not long before the end of the war, in April 1998: Remus Lupin turns up at Shell Cottage to announce the birth of his son (which is hot news and has presumably occurred either that day or not more than a day or two earlier) on what is identified as "one blustery April evening". And we can narrow it down a bit further.

The trio were captured and taken to the Malfoy manor-house just after listening to the resistance radio programme, which was identified as occurring in March. Draco was home for the Easter holidays, and Easter Sunday that year was actually on 12^th April. If that held true for the wizarding world then the scene at Malfoy Manor must have been at the very end of March - two weeks before Easter Sunday, and at the very beginning of the Easter holiday. The Trio arrived at Shell Cottage the following morning, so at the very end of March or very beginning of April. We are then told that "the days stretched into weeks" prior to Lupin's announcement: we don't know how many weeks, but clearly at least two, so we can say that Teddy Lupin was born in mid to late April 1998.

Nineteen Years LaterAutumn seemed to arrive suddenly that year. The morning of the first of September was crisp and golden as an apple, [DH Epilogue; p. 601-603]

[cut]the red-headed girl trailed tearfully behind her brothers, clutching her father's arm.
       'It won't be long, and you'll be going too,' Harry told her.
       'Two years,' sniffed Lily. 'I want to go now!'
       [cut] Albus's voice drifted back to Harry over the surrounding clamour; his sons had resumed the argument they had started in the car.
       'I won't! I won't be in Slytherin!' [DH Epilogue; p. 603]

'We wrote to James three times a week last year,' said Ginny. [DH Epilogue; p. 603]

Rose, who was already wearing her brand new Hogwarts robes, [DH Epilogue; p. 604]

Back on the platform, they found Lily and Hugo, Rose's younger brother, having an animated discussion about which house they would be sorted into when they finally went to Hogwarts. [DH Epilogue; p. 604]

Draco Malfoy was standing there with his wife and son, [cut] The new boy resembled Draco as much as Albus resembled Harry.
'So that's little Scorpius,' [DH Epilogue; p. 605]

'Teddy's back there, [cut] Snogging Victoire!' [DH Epilogue; p. 605]

'Albus Severus,' Harry said quietly, [cut] 'you were named for two headmasters of Hogwarts.' [DH Epilogue; p. 607]

We know that the scene at King's Cross at the very end of DH is set nineteen years after the end of the war because that's what the first page of the epilogue says: "Nineteen Years Later". Knowing that the war ended in 1998, we can calculate that this scene takes place on 1^st September 2017.

Since they are observed kissing, Bill and Fleur's daughter Victoire Weasley is presumably in roughly the same age bracket as Teddy. JK Rowling's hand-drawn Weasley family-tree shows her as the eldest of three children, Victoire, Dominique and Louis. Teddy, born in April 1998, would have left Hogwarts in summer 2016, yet he is there at King's Cross in the epilogue, presumably to see Victoire. She might have been there to help see her younger siblings onto the train, but since Teddy apparently knew for sure that she would be there, and is kissing her on the platform as if he won't have the chance to do so later and more privately, it's likely that she herself is two years (at least) younger than him and is still a student. She was probably born between 2^nd September 1999 and 1^st September 2000, and Dominique and Louis Weasley are younger.

STOP PRESS! Rowling has apparently now fixed Victoire's birthdate as 2^nd May 1999. That means that unless she was somehow held back a year, she ought to have been at Hogwarts 2010-2017, and therefore has already finished at Hogwarts in this scene. Which doesn't make much sense. Or Rowling has miscalculated again.

Harry and Ginny's daughter Lily - identified in JK Rowling's hand-drawn Weasley family-tree as Lily Luna Potter - is two years too young to start at Hogwarts. Unless the rules have changed, this means that she is nine, and was born between 2^nd September 2007 and 1^st September 2008.

Harry and Ginny's son Albus Severus Potter is just starting at Hogwarts, as are Ron and Hermione's daughter Rose Weasley and Draco's son Scorpius Malfoy. This means that they are all eleven, and were born between 2^nd September 2005 and 1^st September 2006.

Harry and Ginny's son James - identified in JK Rowling's hand-drawn Weasley family-tree as James Sirius Potter - has been at Hogwarts for at least a year. It rather sounds in the text as if he has been there only a year, since Harry refers to all the letters he sent to James last year, not the last two years. However, Rowling marked James's going-to-Hogwarts day on 1^st September 2015, and though this may well have been an error (she initially marked Albus Severus's going-to-Hogwarts day a year early on 1^st September 2016, until the error was point out to her), she has since set it in stone by saying that James is two years older than Albus Severus, and Lily Luna is two years younger. So James was born between 2^nd September 2003 and 1^st September 2004, and Lily between 2^nd September 2007 and 1^st September 2008.

Ron and Hermione son Hugo Weasley is younger than Rose and too young to start at Hogwarts, but he is clearly not a toddler, since he is discussing Hogwarts houses animatedly with Lily Luna. He must be at least six and not more than ten, so he was born between 2^nd September 2006 and 1^st September 2011. Also, since he is Rose's younger brother and is not her twin, he must be at least nine months younger than her.

JK Rowling's hand-drawn Weasley family-tree shows Luna and her husband Rolf having two sons, Lorcan and Lysander Scamander. Although it isn't apparent in the drawing, interview-canon is that Lorcan and Lysander are twins, and also that Luna found a partner rather late, plus we do not see her at King's Cross in the Epilogue, so it is likely that the boys are too young to have started at Hogwarts as at 2017, and were born no earlier than 2^nd September 2006.

Conclusion:

We can summarize what we know as follows:

Birthdates and Hogwarts attendance, to best approximation
Name	Day	Month	Year	Comments	Attended Hogwarts
Bathilda Bagshot			1857	or earlier
Regulus Black		last quarterish, prob. December but could be as early as late September	1961	or could be as late as January 1964 if we discount the Black family tree	Prob. 1973/1979, dying partway through the 1979-1980 academic year.
Sirius Black	3	November	1959		1971/1978
Colin Creevey			1981	Between early May 1981 and 31^st August 1981.	1992/1997 (expelled after fifth year due to being Muggle-born, killed at the end of sixth year).
Dennis Creevey			1982/83	Between 1^st September 1982 and 31^st August 1983.	1994/2002 (he would have had to re-take a year, since he missed the year 1997/98 due to being Muggle-born).
Cedric Diggory		early September	1977	Killed at the end of his sixth year at Hogwarts.	1989/1995
Dobby	28	June		Year unknown, lifespan unknown
Elphias Doge			1880/81	Between September 1880 and August 1881.	1892/1899
Aberforth Dumbledore		probably summer	1884	assuming him to be three years younger than Albus.	circa 1895/1902
Albus Dumbledore		late July or August	1881		1892/1899
Ariana Dumbledore		Probably spring	1885	assuming her to be four years younger than Albus.
Dudley Dursley	30	June	1980	or 23^rd June
Petunia Dursley (née Evans)			1958	approximately
Vernon Dursley	11	September	1956	Given on the Michief Wiki, source unknown - possibly just fanon?
Filius Flitwick	17	October		Year unknown but probably considerably pre 1900 - possibly even pre 1800, depending on what the dash of goblin blood has done to his life-span.
Hermione Granger	19	September	1979		1991/1998
Gellert Grindelwald		late spring or summer	1882
Rubeus Hagrid	6	December	1928		1940/1943 (expelled late in third year).
Angelina Johnson		October	1977	last week in October	1989/1996
Bertha Jorkins				Two or three academic years above Sirius.	1968/1975 or 1969/1976
Viktor Krum		August	1976	Probably first two weeks in August, otherwise some time in July.	Durmstrang 1988/1994, Hogwarts 1994/1995.
Bellatrix Lestrange		Prob. last quarter	1951	Could be as late as 1955 if we discount the Black family tree and Andromeda left school after OWLs.	Prob. 1963/1968 & 1970/1972.
Neville Longbottom	30	July	1980		1991/1998
Luna Lovegood			1980/81	Between 1^st September 1980 and early May 1981.	1992/1999
Remus Lupin	10	March	1960		1971/1978
Teddy (Edward? Theodore?) Lupin		mid to late April	1998		2009/2016
Draco Malfoy	5	June	1980		1991/1998
Lucius Malfoy			1953/54	Between mid-September 1953 and mid-September 1954.	1965/1972 or 1966/1973
Narcissa Malfoy		April?	1955	according to the Black family tree.	1966/1973 or 1967/1974
Scorpius Malfoy			2005/2006	Between 2^nd September 2005 and 1^st September 2006.	2017/2024
Griselda Marchbanks			1872	or earlier
Minerva McGonagall	4	October	1935	if we accept Pottermore as canon, otherwise 1923 or 1924.	1947/1954
Albus Severus Potter			2005/2006	Between 2^nd September 2005 and 1^st September 2006.	2017/2024
Harry Potter	31	July	1980		1991/1998
James Potter	27	March	1960		1971/1978
James Sirius Potter			2003/2004	Between 2^nd September 2003 and 1^st September 2004	2015/2022
Lily Potter (née Evans)	30	January	1960		1971/1978
Lily Luna Potter			2007/2008	Between 2^nd September 2007 and 1^st September 2008.	2019/2026
Muriel Prewett			1890	or 1889, if her birthday is later than early August, since she is 107 in early August 1997.
Tom Riddle	31	December	1926		1938/1945
Lorcan & Lysander Scamander			2006 or later	On or after 2^nd September 2006.	2018/2025, or later
Horace Slughorn			1908	give or take about five years
Enid Smeek			1884	or earlier
Severus Snape	9	January	1960		1971/1978
Pomona Sprout	15	May	1931	if she was five academic years above Minerva McGonagall; 1941 if she was five years below her	1942/1949 or 1952/1959
Andromeda Tonks				Not earlier than summer 1951 nor later than August 1954, assuming she sat NEWTs; if she left school before NEWTs, could be as late as early 1955.	Between 1962/1969 & 1965/1972 if she sat NEWTs.
Nymphadora Tonks			1972/73	Between September 1972 and August 1973.	1984/1991
Arthur Weasley	6	February	1951	Could be earlier than 1951 or as recent as 1955 but 1951 is the most likely year; either way he must be either the same calendar year as Molly Weasley, q.v., or a year younger.	Either one academic year above Molly Weasley, q.v., or the same year, depending on whether he is eight months older or four months younger than her.
Charlie Weasley	12	December	1972	or 1973, but if so he was Seeker in his first year	1985/1990, 1984/1989 or possibly 1984/90: either way internal evidence suggests he left Hogwarts at least a year before he would have been due to sit NEWTs
Dominique Weasley			2000 or later	At least nine months (eight if a bit premature) after Victoire Weasley.	After Victoire, who probably attended 2011/2018
Fred & George Weasley	1	April	1978		1989/1996
Ginevra (Ginny) Weasley	11	August	1981		1992/1999
Hugo Weasley			2006 or later	Between 2^nd September 2006 and 1^st September 2011, and at least nine months younger than Rose Weasley (eight months at a pinch if a bit premature).	As early as 2018/2025, or as late as 2022/2029
Louis Weasley			2000 or later	At least nine months (eight if a bit premature) after Dominique Weasley.	After Dominique, who probably attended no earlier than 2012/2019
Molly Weasley	30	October	1950	1950 is the most recent year she could have been born in and still have done a full seven years at Hogwarts and left before Bill was conceived, assuming Bill was born in 1970. If he was born in 1971 she could be a year younger; if he was born in 1971, and she left school after OWLs, pregnant, she could have been born as recently as 1954. She could also have been born prior to 1950, but not by more than two years, because she eloped soon after leaving school and at that time Voldemort was already an obvious threat.	1962/1969 - 1963/1970 if Bill was born in 1971 - or earlier: assuming she sat NEWTs and wasn't pregnant at the time.
Percy Weasley	22	August	1976		1987/1994
Ron Weasley	1	March	1980		1991/1998
Rose Weasley			2005/2006	Between 2^nd September 2005 and 1^st September 2006.	2017/2024
Victoire Weasley	2	May	1999		2010/2017
William (Bill) Weasley	29	November	1970	or 1971 if Charlie was born in 1973.	1982/1989, or 1983/1990, or possibly 1982/1990 if he repeated a year: if he left in 1989 he must have revisited the school in summer 1990.