I suppose there's no definitive answer to this question (although if there is, I'd love to know it): how old is Azedarac? That is, from what time does he originate? Is he a native to the 5th century as is might be implied by "The Holiness of Azedarac." or is he older still? Since he had an original Hyperborean version of the Book of Eibon, I wouldn't be surprised if he were far older, but who can say?

That's the trouble when dealing with time-travelling wizards, you just can't tell when they'll show up next! It does seem to me that the antecedents of Azedarac were rumored to be shrouded in mystery, as implied in these comments by Moriamis: "He was the wisest and mightiest of sorcerers, and the most secret withal; for no one knew the time and the manner of his coming into Averoigne, or the fashion in which he had procured the immemorial Book of Eibon,"
So it seems very likely that Azedarac, even if he was not a native of Hyperborea, must have visited this ancient land at least once, perhaps for the express purpose of obtaining the original Hyperborean text of Eibon. At least, that's my take on the matter.
-Ron