Após o Phoenix parece ser o que você está procurando.
As seguintes linhas da história são consistentes com o corpo da sua pergunta.
Twelve hundred years old. Of course, Peverell had been asleep for most of the time. Not physically dead and kept under preservation charms as Harry had expected at first...the enchanted sleep Ignotus Peverell had placed himself under a thousand years ago, had actually kept his essential functions alive.