Desconhecido
J.K. Rowling só falou uma vez sobre o passado de Fawkes
Peter Humphreys for BBC Newsround - Who did Fawkes previously belong to and will he play a vital role in the next book?
JK Rowling: I am not going to answer about the role in the next books, which probably gives you a big clue, and he has never been owned by anyone but Dumbledore. You will notice that when Harry goes back in the Pensieve in this book, Fawkes is never there, and no, I am sorry, not in this book, I take that back. When Harry has previously seen the study with a different headmaster he saw it with Dippet and Fawkes was not there then. Fawkes is Dumbledore's possession, not a Hogwarts possession.
(Edinburgh "cub reporter" press conference, ITV, 16 July 2005)
O HP wiki gosta de ressaltar que o fato de que sua pena forneceu o núcleo para a varinha de Voldemort colocaria um mínimo na sua idade como tendo nascido um pouco antes de 1938.
Claro, Fawkes viveu na natureza antes de Dumbledore domesticá-lo, e ele provavelmente não forneceu as penas da varinha até algum ponto posterior. Bestas Fantásticas e Onde Habitam nos dizem que a Fênix geralmente vive para "um imensa idade ", então nós realmente não temos como saber quantos anos Fawkes é.“Exactly,” said Dumbledore. “Harry’s wand and Voldemort’s wand share cores. Each of them contains a feather from the tail of the same phoenix. This phoenix, in fact,” he added, and he pointed at the scarlet-and-gold bird, perching peacefully on Harry’s knee.
“My wand’s feather came from Fawkes?” Harry said, amazed.
“Yes,” said Dumbledore. “Mr. Ollivander wrote to tell me you had bought the second wand, the moment you left his shop four years ago.”
(Harry Potter and the Goblet of FIre - Chapter 36)
The phoenix lives to an immense age as it can regenerate, bursting into flames when its body begins to fail and rising again from the ashes as a chick.
(Fantastic Beasts and Where To FInd Them - Phoenix)