Nicholas Flamel, mentioned as the creator of the Philosopher's Stone,
was actually a real alchemist who was believed by some people to have produced
the Philosopher's Stone and who has mysterious circumstances surrounding his
"death". It is rumored that he might still be alive and, if so, he would be
about the age given in the book and movie.
You can find a very detailed and interesting description of this at
"Nicholas Flamel: The Immortal French