There are some elders who whisper that the Ancients have always existed, and always will exist -- unknowable eldritch tentacle-shards of a mad moon, outside of time, doomed to battle forever. Other elders eyeball it at around ten, maybe thirteen years. It really depends what wizard you’re listening to in the forest. Either way, we tend to side with the elders who say “Look, it’s got to be something,” and ten’s a nice round number.