Harry Potter Go
The young cast of Harry Potter and the Philosopher's Stone.Warner Bros

It has been 20 years since Harry Potter met Ron and Hermione – and He-Who-Must-Not-Be-Named – for the first time in the Philosopher's Stone, marking the start of Harry's magical adventure.

Author JK Rowling has often told the story of how she received "loads" of rejections before Harry Potter and the Philosopher's Stone was finally published on 26 June 1997.

Twenty years on, seven books, eight films and one play later, we're still obsessed with Harry Potter, Hogwarts and the wizarding world.

On the anniversary, here are 20 facts about Potter and the franchise.

  1. The Dementors are based on Rowling's battle with depression following the death of her mother, who had multiple sclerosis, in 1990.
  2. Hermione's patronus is an otter, but Ron's is a Jack Russell Terrier.
  3. Dumbledore is an Old English word meaning "bumblebee."
  4. The original Dumbledore, Richard Harris, sadly passed away shortly before the Chamber of Secrets was released. Michael Gambon took over as the character in the rest of the films.
  5. Fred and George were born on April Fools' Day.
    Dumbledore
    Michael Gambon played Albus Dumbledore in the Harry Potter films following the death of the original actor Richard HarrisWarner Bros
  6. The name Hermione is the female derivative of 'Hermes' – a messenger god known for his wit and ability to transition between worlds. Like Hermes, muggle-born Hermione travels between the wizarding and muggle worlds.
  7. Fourteen Ford Anglias were wrecked during the filming of the Whomping Willow scene, in which Harry and Ron crash into the tree with a flying car.
  8. Harry, Ron and Hermione all got their own Chocolate Frog cards.
  9. Voldemort was 71 when he died in the Battle of Hogwarts at the finale of Potter's journey.
  10. Shirley Henderson, the actress who played Moaning Myrtle, was 36 when she played the bathroom-haunting 14-year-old student who was killed by a basilisk's stare.
    Sorting hat
    Dame Maggie Smith as Professor Minerva McGonagall in Harry Potter and the Philosopher's StoneWarner Bros
  11. In 2007, when asked by a fan if the Hogwarts headmaster had ever been in love, Rowling said: "I always thought of Dumbledore as gay."
  12. JK Rowling was offered the role of Lily Potter in the Mirror of Erised scene, but she turned it down and the part went to Geraldine Somerville.
  13. Snape's patronus took the shape of a doe when he fell in love with Lily Potter.
  14. Domhnall Gleeson, the actor who portrays Bill Weasley, is the son of Brendan Gleeson, who plays Mad Eye Moody.
  15. The actor who played the young Tom Riddle is related to the actor who played Voldemort.
    Alan Rickman dies aged 69
    Alan Rickman as Professor SnapeWarner Bros
  16. A magical quill detects and records the birth of every witch or wizard, who are then contacted via owl by Professor McGonagall when they turn 11.
  17. In the scenes where Harry, Ron and Hermione are doing schoolwork, they were actually doing their real homework on set.
  18. Harry's birthday is 31 July 1980. Rowling's birthday is also 31 July - but in 1966.
  19. Tom Felton, who played the part of Malfoy, originally auditioned for the parts of Harry and Ron.
  20. Numbers play a big part of the Harry Potter franchise, in particular, the number 7. There are seven books, seven floors in Hogwarts and seven articles guarding the Philosopher's Stone in the first book.