1. ROWLING AND HARRY SHARE A BIRTHDAY.

They both blow out candles on July 31 (happy birthday, JKR!). And that’s not the only influence Rowling had on her characters: She’s said that Hermione is a bit like her when she was younger, and her favorite animal is an otter—which is, of course, Hermione’s patronus. Plus, both Dumbledore and Rowling like sherbet lemons (Rowling said that the wizard’s “got good taste”).

2. SHE INVENTED THE NAMES OF THE HOGWARTS HOUSES ON THE BACK OF A BARF BAG.

In 2000, Scholastic gave schoolchildren across the U.S. the opportunity to ask Rowling questions about Harry Potter. When one student asked her, “What made you think of the people’s names and dormitories at Hogwarts?” Rowling responded, “I invented the names of the Houses on the back of an airplane sick bag! This is true. I love inventing names, but I also collect unusual names, so that I can look through my notebook and choose one that suits a new character.”

3. EARLY ON, ROWLING WROTE A SKETCH OF THE FINAL CHAPTER OF THE FINAL BOOK.

Rowling calls the idea that she had the first chapter of Deathly Hallowswritten and locked away in the safe “rubbish.” But there was a small element of truth to it: “I had, very early on—but not the first day or anything, probably within the first year of writing—I wrote a sketch for what I thought the final chapter would be,” she told Harry Potter’s big screen portrayer, Daniel Radcliffe, in an interview for the Deathly Hallows Part 2 DVD extra features. “I always knew—and this was from really early on—that I was working toward the point where Hagrid carried Harry, alive but supposedly dead, out of the forest, always. I knew we were always working towards a final battle at Hogwarts, I knew that Harry would walk to his death, I planned the ghosts—for want of a better word—coming back, that they would walk with him into the forest,  we would all believe he was walking to his death, and he would emerge in Hagrid’s arms.”
And that mental image is what kept Hagrid alive, despite the fact that he “would have been a natural to kill in some ways,” Rowling said. “But because I always cleaved to this mental image of Hagrid being the one carrying Harry out … That was so perfect for me, because it was Hagrid who and took him into the world, and Hagrid who would bring him back … That’s where we were always going. Hagrid was never in danger.”

4. THE DEMENTORS ARE BASED ON ROWLING’S STRUGGLE WITH DEPRESSION AFTER HER MOTHER’S DEATH.

Rowling’s mother, who had multiple sclerosis, died in 1990, after which Rowling suffered a period of depression. She would use the experience to characterize the Harry Potter’s dementors, creepy creatures that feed on human emotion. “It’s so difficult to describe [depression] to someone who’s never been there, because it’s not sadness,” Rowling told Oprah Winfrey. “I know sadness. Sadness is to cry and to feel. But it’s that cold absence of feeling—that really hollowed-out feeling. That’s what Dementors are.”

5. SHE CREATED QUIDDITCH AFTER A FIGHT WITH HER BOYFRIEND.

“If you want to create a game like Quidditch, what you have to do is have an enormous argument with your then-boyfriend,” Rowling said in 2003. “You walk out of the house, you sit down in a pub, and you invent Quidditch. And I don’t really know what the connection is between the row and Quidditch except that Quidditch is quite a violent game and maybe in my deepest, darkest soul I would quite like to see him hit by a bludger.”

6. THE WIZARDING WORLD’S PLANTS COME FROM A REAL BOOK.

“I used to collect names of plants that sounded witchy,” she told 60 Minutes, “and then I found this, Culpeper’s Complete Herbal, and it was the answer to my every prayer: flax weed, toadflax, fleawort, Gout-wort, grommel, knotgrass, Mugwort.” The book was penned in the 17th century by English botanist and herbalist Nicholas Culpeper; you can read it here.

7. A PROPOSED TITLE FOR THE AMERICAN VERSION OF PHILOSOPHER’S STONE WAS HARRY POTTER AND THE SCHOOL OF MAGIC.

Rowling turned that down, saying, according to American publisher Arthur Levine, “No—that doesn’t feel right to me … What if we called it the Sorcerer’s Stone?” (The French edition, Levine points out in J.K. Rowling: A Bibliography, is called Harry Potter a L’ecole Des Sorciers.)

8. ROWLING MADE COMPLICATED OUTLINES FOR THE BOOKS.

Click to enlarge.
You can see a partial outline for Order of the Phoenix above. The outline has chapter titles, a general outline of the plot, and then more specific plot points for certain characters. (Based on this outline, it looks like Rowling thought about calling Dolores Umbridge Elvira Umbridge instead!)

9. ARTHUR WEASLEY WAS SUPPOSED TO DIE.

In a battle between good and evil this epic, not everyone would make it through alive—that would have led to “very fluffy, cozy books,” she told Meredith Vieira. “You know, suddenly I [would be] halfway through Goblet of Fire and suddenly everyone would just have a really great life and … the plot would go AWOL.”
Which is not to say that Rowling knew exactly who was on the chopping block. She thought about killing Arthur Weasley after he’s attacked by Nagini in Order of the Phoenix, but instead opted to save him, partly because “there were very few good fathers in the book. In fact, you could make a very good case for Arthur Weasley being the only good father in the whole series.” (She also “seriously considered” killing Ron, then thought better of it.)
Instead, Lupin—a character she had no intention of killing when she began the books—and Tonks died during the final Battle of Hogwarts. “I wanted there to be an echo of what happened to Harry just to show the absolute evil of what Voldemort’s doing,” she said. “I think one of the most devastating things about war is the children left behind. As happened in the first war when Harry’s left behind, I wanted us to see another child left behind. And it made it very poignant that it was [Lupin and Tonks’s] newborn son.”

10. TO KEEP DEATHLY HALLOWS FROM LEAKING EARLY, BLOOMSBURY GAVE IT CODENAMES.

You probably wouldn’t have been so interested in reading Edinburgh Potmakers or The Life and Times of Clara Rose Lovett: An Epic Novel Covering Many Generations.

11. HALEY JOEL OSMENT COULD HAVE PLAYED HARRY.

When Steven Spielberg was attached to direct the film adaptation, he wanted Sixth Sense star Haley Joel Osment to play Harry. But the director eventually left over a creative clash with Rowling, and new director Chris Columbus had to find his star. Some 300 kids tested for Harry Potter over a period of seven months; Jonathan Lipnicki (Jerry McGuire) even expressed interest. “There were times when we felt we would never find an individual who embodied the complex spirit and depth of Harry,” Columbus said.
Then, one night, Heyman went to the theater with screenwriter SteveKloves (who ended up penning all but one of the Potter scripts). “There sitting behind me was this boy with these big blue eyes. It was Dan Radcliffe,” he told HeroComplex in 2009. “I remember my first impressions: He was curious and funny and so energetic. There was real generosity too, and sweetness. But at the same time he was really voracious and with hunger for knowledge of whatever kind.” He persuaded Radcliffe’s parents to let their son audition, and the rest is history.

12. RUPERT GRINT’S AUDITION WAS UNUSUAL.

Nine-year-old Emma Watson’s first audition for the role of Hermione took place in her school gym; she auditioned a total of eight times. Grint, then 10, sent in a video audition, and went in a rather unusual direction: “I found out that you could audition by sending a picture of yourself and some information to Newsround,” he said in 2002. “I did my own video with me, first of all, pretending to be my drama teacher who unfortunately was a girl and then I did a rap of how I wanted to be Ron and then I made my own script thing up and sent it off.”
He had some competition, though: Tom Felton auditioned for both Ron and Harry before ultimately being cast as Draco Malfoy.

13. THERE’S A VERY GOOD REASON HARRY’S EYES AREN’T GREEN IN THE MOVIES.

In the books, Harry’s eyes are described as “bright green”—but Radcliffe’s are blue. When Sorcerer’s Stone was in pre-production, Heyman called Rowling and told her their options: They’d tried green contacts; they could also trying making Radcliffe’s eyes green in post-production. How important was it, he wondered, for Harry’s eyes to be green?
Rowling said that the only thing that was really important was that Harry’s eyes looked like his mother’s eyes, so whoever played Lily Potter would need to have some resemblance to Radcliffe. This was a relief for Radcliffe, who had an an extremely adverse reaction to the contacts. (He was also allergic to the glasses, which made him break out in acne.)

14. THE BROOMS USED IN THE SERIES AREN’T REGULAR BROOMS.

They were made by modeler Pierre Bohanna using aircraft-grade titanium. “People think of them as a prop the kids are carrying around, but in reality, they have to sit on them,” Eddie Newquist, chief creative officer of the firm Global Entertainment Services, which puts on Harry Potter: The Exhibition, told Popular Mechanics. “They have to be mounted onto motion-control bases for green-screen shots and special-effects shots, so they have to be very thin and incredibly durable. Most of these kids weighed 80 pounds, 90 pounds [at the beginning]. Now they’re all adults, so they’re up over 120, 130 pounds, and you have to really make sure your brooms can withstand that.”

15. THE ROLE OF PEEVES WAS CAST AND FILMED—THEN CUT.

British comedian Rik Mayall was cast as Hogwarts’s prank-happy poltergeist in Harry Potter and the Sorcerer’s Stone. He showed up and shot the scenes, which were later cut when director Chris Columbus decided he didn’t like the look of the ghost. Mayall described the experience in a 2011 interview:
He didn’t tell his kids his part had been cut, though, and when they went to see it, “they came back and they said: ‘Bloody good make up. You didn’t look like yourself at all dad,’” Mayall said. “They thought I was playing Hagrid, Robbie Coltrane’s part.”

16. THE ACTRESS WHO PLAYED MOANING MYRTLE WAS MUCH OLDER THAN A STUDENT.

Shirley Henderson was 36 when she played the bathroom-haunting ghost of a 14-year-old student who was killed by a basilisk’s stare in Chamber of Secrets. Playing a ghost was tougher than playing a real person, she told the BBC, “because of all the technical stuff it involved. I had to be strapped up to this harness so it looked as if I was flying and so I could be pushed through the air and twisted and turned over and over again. It’s physically very tiring on your body. It also requires a lot of concentration, because there’s all kinds of people shouting stuff like ‘Turn, do this, look at this’ so they can do all their stuff with the computer effects while I’m trying to act it out. But once you block all that out, it’s great fun. Really good fun.”

17. PRISONER OF AZKABAN DIRECTOR ALFONSO Cuarón ASKED THE TRIO TO WRITE ESSAYS ABOUT THEIR CHARACTERS.

Alfonso Cuarón wanted Watson, Radcliffe, and Grint to write essays about their characters from a first person point of view. According to Heyman, “they all responded very much in character … Dan wrote a page, Emma wrote 10 and Rupert didn’t deliver anything.” Grint told Entertainment Weekly, “I didn’t do mine, because I didn’t think Ron would. Or that was my excuse. At the time, I was actually quite busy with the real schoolwork involved with my exams, and I just didn’t do it. But in the end, it felt right because that’s what Ron would have done.”

18. ROWLING SHOT DOWN ONE OF Cuarón’S IDEAS.

Rowling wasn’t precious about all of the details of her books (see: Harry’s eye color). “Inevitably, you have to depart from the strict storyline of the books,” she told Radcliffe. “The books are simply too long to make into very faithful films.” But that didn’t mean she’d let everything slide: “Sometimes I would dig my heels in on the funniest things,” she said. “I’d say yeah, change the costume, that’s not a problem … And then all of a sudden I’d say, ‘Why would they do that spell? They wouldn’t do that there.’”
Take, for example, one shot that Cuarón wrote into Prisoner of Azkaban, which Rowling called “rather bizarre.” “I think Flitwick was conducting, and there were miniature people in an orchestra inside something,” she told Radcliffe. “I said to him, but why? I know it’s visually exciting, but part of what I think fans really enjoyed about the literary world is that there was a logic that underpinned it. There was always a logic to the magic, however strange it became. And I know it’s intriguing to go through the mouth of whatever it was and see these little people, but why have they done it? For you to film it, that’s just what it feels like. Normally, with the magic, there’s a point. So we had a bit of discussion.”

19. ROWLING TIPPED ALAN RICKMAN OFF TO SNAPE’S MOTIVATIONS.

“I told him really early on that Snape had been in love with Lily, that’s why he hated James, that’s why he projected this amount of dislike onto Harry,” Rowling told Radcliffe. “So he knew that. Then you told me that he’d been saying … ‘I just don’t think Snape would do that, given what I know.’” She laughed, continuing, “And I thought, ‘Alan, are you really milking this now?’”
She also tipped Radcliffe off to Harry’s (partial) fate after seeing him in Equus. Radcliffe asked her, point blank: “Do I die?”
“You get a death scene,” Rowling told him.
“I saw you double-take,” Rowling said. “Neal, my husband, afterward, said, ‘What did Dan ask you?’ And I said ‘He wanted to know if he’s going to die.’” When he asked what she’d said, Rowling told him, “I’m not telling you!” Though her husband was tipped off to Dumbledore’s fate ahead of time, Rowling kept Harry’s ultimate fate a secret till the end.

20. THE ACTORS COULDN’T PLAY CONTACT SPORTS.

Instead, they played golf. ”[At Leavesden Studios], Rupert Grint and my brother [James] and I would hang out at the driving range downstairs quite a bit,” Oliver Phelps, who played George Weasley, told EW. “I mean, I say driving range, but it was a mat and a 150-yard cone at the other end. Golf was one of the only sports we were allowed to do in our contract because it was relatively quite safe. We couldn’t do any contact sports.”

21. THE MOVIES FEATURED SOME HIGH TECH VISUAL EFFECTS …

Visual effects artists were tasked with bringing many of the fantastic magical elements of Harry Potter to life, including everything from fire-breathing dragons and club-swinging giants to zombie-like Inferi and Voldemort’s snake-like face (which was created by using practical makeup and digitally removing Ralph Fiennes’s nose). One of their most challenging sequences came early in Deathly Hallows, when members of the Order of the Phoenix arrive at Privet Drive to whisk Harry away to a safe spot. Multiple Harrys, Mad-Eye Moody says, will confuse the Death Eaters on their trail—so some of the wizards chug Polyjuice Potion and transform into Harry.
The transformation was tough for visual effects artists to pull off. “We needed to have a little bit of the attributes of Harry, and a little bit of the attributes of whoever we started with—George, Fred, Ron, Hermione,” Nicolas Aithadi, VFX supervisor at Moving Picture Company, told Popular Mechanics. “The tricky part is you have to be able to read the Harry part and the George part. What we keep from each of these characters has to be perfect.” They accomplished it by coating the actors’ faces in UV paint, then having them make faces in the Mova Contour Reality Capture system, which has 29 cameras and can capture 50,000 points of information, creating a 3D mesh cloud they could use as a basis for the transforming faces.
According to Phelps, it was completely different than anything they’d ever done before. “There are probably 30 different facial expressions they tried to get you to do,” he told Popular Mechanics. “I never realized how wide I could open my mouth until we did that scene, so that was quite cool.” Because of the UV paint, the VFX artists had one piece of advice, Phelps said: “They were quite keen to say, ‘Just don’t go to any nightclubs tonight, because you’ll look like a floating head.’”

22. … BUT NOT ALL THE EFFECTS WERE COMPUTER GENERATED.

Animatronics were made for the actors to interact with on set, including baby mandrakes, Hedwig, the Monster Book of Monsters, and Buckbeak, which was used on-set for close ups. “He could stare at you, his eyes could follow you, he could bow, and every one of his feathers was dyed and put in by hand,” Newquist told PopMech. “There are tens of thousands of them, and they look absolutely gorgeous.”Other creatures were built to give the animators reference for lighting, like the giant Jack-in-the-Box from Prisoner of Azkaban and house elf Kreacher.

23. THE FILM’S MAKEUP ARTISTS APPLIED THE LIGHTNING BOLT SCAR MANY, MANY TIMES OVER THE COURSE OF EIGHT FILMS.

Five thousand eight hundred times, to be exact. In our 2014 interview with Radcliffe, he told us, “The lightning scar, on the first two films, we essentially painted it on, and after that we used Pros-Aide, which was like a glue [to put it on]. It was very simple.” The scar was applied to his face 2,000 times; the rest went on film and stunt doubles. Radcliffe also went through 160 pairs of Harry’s round-frame glasses.

24. HELENA BONHAM CARTER KEPT HER BELLATRIX TEETH.

“I loved my [fake] teeth!” the actress told EW. “I kept them because they’re not going to fit anybody else. I keep them in a blue plastic thing in the bathroom and bring them out when I miss [Bellatrix].’”

25. THERE COULD HAVE BEEN AN OFFICIAL HARRY POTTER MUSICAL.

Rowling has turned down a lot of proposed Harry Potter ideas—including, she told Winfrey, a musical that Michael Jackson wanted to do. Earlier this year, Rowling announced that she’s working with a team to bring a new Harry Potter story to the stage; Harry Potter and the Cursed Childwill hit the West End in 2016.

26. DUMBLEDORE WAS GAY.

In 2007, when asked by a fan whether or not Hogwarts’s favorite headmaster had ever been in love, Rowling responded, “I always thought of Dumbledore as gay.” She revealed that he had fallen in love with Grindelwald, “and that added to his horror when Grindelwald showed himself to be what he was.”
Rowling said she found the reaction to the news very interesting. “To me it was not a big deal,” she told Radcliffe. “This is a very old man who has a very terrible job to do. And his gayness is not really relevant. Very relevant to him as a character, because I always saw him as a very lonely character. And I think that there is in fact a hint of it in [Deathly Hallows] because of the relationship he has with Grindelwald. He fell very hard for this boy …  And don’t you think it was perfect that Dumbledore, who is always the great champion of love … his one great experience of love was utterly tragic.”
This led to one very necessary tweak to the Half-Blood Prince script. “In an early draft of that script, Dumbledore said to Harry … ‘I remember a young woman with eyes of flashing whatever, raven-haired…’ and I read this and I scribbled on my copy of the script, ‘Steve, Dumbledore is gay,’ shoved it up the table,” she said. “And Steve [said,] ‘Oh.’ So that’s why that line didn’t make the film.”

27. ROWLING ACKNOWLEDGED THAT A HARRY/HERMIONE PAIRING MIGHT HAVE WORKED.

In an interview with Emma Watson for Wonderland magazine in 2014, Rowling said that “I wrote the Hermione/Ron relationship as a form of wish fulfillment,” saying that they ended up together “for reasons that have very little to do with literature and far more to do with me clinging to the plot as I first imagined it … The attraction itself is plausible but the combative side of it … I’m not sure you could have got over that in an adult relationship, there was too much fundamental incompatibility.”
She noted that “in some ways Hermione and Harry are a better fit,” and that she felt that “quite strongly” when she wrote a particular scene in Deathly Hallows, where Harry and Hermione are in the tent. “I hadn’t told [Steve] Kloves that and when he wrote the script he felt exactly the same thing at exactly the same point,” she said.

28. BACK IN THE DAY, THE MALFOYS HUNG OUT WITH RICH MUGGLES.

“Until the imposition of the Statute of Secrecy in 1692, the Malfoy family was active within high-born Muggle circles, and it is said that their fervent opposition to the imposition of the Statute was due, in part, to the fact that they would have to withdraw from this enjoyable sphere of social life,” Rowling wrote on Pottermore. In fact, one Malfoy might have had designs on the British Throne: “There is ample evidence to suggest that the first Lucius Malfoy was an unsuccessful aspirant to the hand of Elizabeth I, and some wizarding historians allege that the Queen’s subsequent opposition to marriage was due to a jinx placed upon her by the thwarted Malfoy,” Rowling writes. The Malfoys gave up their Muggle fraternizing when the Ministry of Magic, “the new heart of power,” was founded.

29. MOANING MYRTLE HAS AN INTERESTING INSPIRATION.

Rowling wrote on Pottermore that the whiny, bathroom-dwelling ghost was inspired by “the frequent presence of a crying girl in communal bathrooms, especially at the parties and discos of my youth. This does not seem to happen in male bathrooms, so I enjoyed placing Harry and Ron in such uncomfortable and unfamiliar territory in Harry Potter and the Chamber of Secrets and Harry Potter and the Half-Blood Prince.”

30. MUGGLES CAN’T MAKE POTIONS.

And that’s because you can’t make potions without wands. “Merely adding dead flies and asphodel to a pot hanging over a fire will give you nothing but nasty-tasting, not to mention poisonous, soup,” Rowling wrote on Pottermore. Though her least favorite subject in school was Chemistry, she admitted that “I always enjoyed creating potions in the books, and researching ingredients for them. Many of the components of the various draughts and libations that Harry creates for Snape exist (or were once believed to exist) and have (or were believed to have) the properties I gave them.”

31. ROWLING’S EDUCATION CAME IN HANDY.

At university, she minored in Classics, and she put that education to good use, peppering the books with Latin. “It just amused me, the idea that wizards would still be using Latin as a living language, although it is, as scholars of Latin will know,” she said in 2000. “I take great liberties with the language for spells. I see it as a kind of mutation that the wizards are using.” Expelliarmus, for example, combines expellere, meaning “drive out” or “expel,” with arma, meaning “weapon,” and knocks weapons from an enemy’s hands. Incendio, which lights a fire, comes from incendiarius, or “fire-raising.” And Hogwarts’s motto is Draco Dormiens Numquam Titillandus—“Never Tickle a Sleeping Dragon.”

32. THERE WAS ONE HARRY POTTER QUESTION ROWLING FEARED THE MOST.

It was “What was Dumbledore’s wand made of?”
“That would have been quite a telling question,” Rowling told Time. “Because I had this elder thing in my mind, cause elder has this association in folklore, it’s the death tree. I thought, ‘What am I going to say?’” Thankfully, no one ever asked.

33. STEPHEN KING THOUGHT DOLORES UMBRIDGE WAS A GREAT VILLAIN.

In his review of Order of the Phoenix for Entertainment Weekly, King said, “The gently smiling Dolores Umbridge, with her girlish voice, toadlike face, and clutching, stubby fingers, is the greatest make-believe villain to come along since Hannibal Lecter” .

34. YOU CAN SPOT A CRUMPLE-HORNED SNORKACK IN THE WIZARDING WORLD OF HARRY POTTER …

It’s on the second story of the Magical Menagerie. Luna’s father, Xenophilius Lovegood, claimed it was a real creature, but it was never found. Rowling said that Luna, who became a naturalist, had to eventually “accept that her father might have made that one up.”

35. … AS WELL AS ARTHUR WEASLEY’S FLYING CAR.