/facepalm. Yeah I'll fix my previous post. Don't know what I was thinking. What I was trying to say is that the AoL backstory doesn't have to take place at the beginning of everything. The only time it needed to do that was in 87 when the game was released, with only one other game out...
Well technically it could work that way. The backstory could take place so far in the past that there was such a large gap of time between it and OoT that everyone had forgotten about the Sacred Realm, or at least how to find it. This was actually the backstory of ALttP, where it said that...