Nicholas Flamel and his wife Petronella (or Perenelle) are mentioned in the first Harry Potter book. According to this, Nicholas and his wife had indeed been enabled to live onwards for more than 600 years using the Philosopher’s Stone. Flamel is described as a partner in alchemy of Albus Dumbledore. The philosopher’s stone is being sought by the evil wizard Lord Voldemort. With the stone, Voldemort hopes to regain his strength and achieve immortality. Voldemort comes very close to getting the stone and is only thwarted by Harry. In consequence, to make certain that Voldemort can never get it, Flamel voluntarily destroys it.
When Dumbledore tells Harry that the stone has been destroyed, Harry is dismayed because Flamel and his wife will now die. However, Dumbledore tells him:
“To one as young as you, I’m sure it seems incredible, but to Nicolas and Perenelle, it really is like going to bed after a very, very long day. After all, to the well-organized mind, death is but the next great adventure.” (Page 297)