User blog comment:Servant of Evillious/The Muzzle of Nemesis Booklet/@comment-149.160.226.79-20150428181701/@comment-6986530-20150501193652

I said it can't be much older than 1500; Held incarnated near the start of the world to monitor Levia-Behemo sealed in the Sin, and the timeline puts that at BT 528. This makes him 1528 by the end time of EC; if the Third Period started in the same year he incarnated then it's also 1528 years old.

You could say there was a gap of time between the start of the world and Levia and Behemo's rebellion in it, but saying that gap could cover almost 3000 years is way too generous. Anything more than three or four years seems like a stretch to me, when all indications are that Levia and Behemo rebelled right at the start and were sealed immediately after rebelling.