Harry Potter has been around since 1997 and the wizarding world is only getting bigger by the year.

But there are some things that even the biggest fans may not know. Here are ten things you didn't know about Harry Potter.

 

1. Rowling and Harry share a birthday

Both J.K. Rowling and Harry Potter blow out their candles on July 31st. Rowling turned 55 this year!

 

2. The actors were not allowed to play contact sport

Oliver Phelps, who played George Weasley said “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.”

 

3. The Dementors were based on Rowling’s struggle with depression

Rowling’s mother, who had multiple sclerosis, died age 45, after which Rowling suffered from depression. She would use the experience to characterize the Harry Potter’s dementors. Rowling said, “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.”

 

4. Moaning Myrtle was a lot older than a student in real life

You might think that the actor who played Moaning Myrtle was around the same age as her character, but you’re wrong!

Shirley Henderson was 36 when she played Moaning Myrtle, the bathroom-haunting ghost of a 14-year-old student who was killed by a basilisk’s stare in Chamber of Secrets.

 

5. Professor Snape is based in large part on J.K. Rowling's old chemistry teacher

Snape was reportedly based, at least in part, on John Nettleship, who taught Rowling chemistry and employed her mother as an assistant at Wyedean School near Chepstow. Rowling based Snape's given name on "Severus Road" in Clapham, and his surname is borrowed from the name of a village in England.

 

6. After Hogwarts, Ginny Weasley became a professional Quidditch player and later joined the sports editorial staff of the Daily Prophet.

J.K. Rowling posted information about how Ginny Weasley decided to follow her passion full-time and become a professional Quidditch player on the website she formed that would continually add to the lore of the Harry Potter franchise.

After Ginny retired from professional Quidditch, she decided to report on her favourite sport. When it came to broadcasting her thoughts on the sport she loved, she thought that The Daily Prophet would be the best place to share her thoughts.

 

7. The young supporting artists who played Hogwarts students were reportedly encouraged to do their real homework while filming

This was to provide realism. Wonder how their teachers reacted when they handed in their homework on prop parchment!

 

8. Months after the film’s release, Russian lawyers threatened a lawsuit against Warner Bros

This was for basing Dobby on the image of Russia’s president Vladimir Putin. Dobby’s ears were based on those of a dog called Max, who would sit under the designer of Dobby’s desks.

 

9. Robin Williams was turned down to play the role of Hagrid

Robin Williams expressed an interest in playing Hagrid in the first Harry Potter film, he was declined due to a surprising rule. The film had a very strict 'British only' rule for the main roles.

10. Muggles can’t make potions

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.