Quote Originally Posted by Temperjoke View Post
Midgard was there before the Allagans, at least, because Bahamut was one of his brood in eggs that traveled with him. That means the covenant with Hydaelyn was in place before the Allagan Empire. The empire didn't encounter Primals until it invaded Meracydia though, after it defeated the dragons living there. That means, the seal only affected the Eorzea continent. This makes sense though that there would be a seal, due to the high volume of aether that the continent has compared to the other continents, it makes it much easier to summon Primals as a result. I'm not sure why Midgard wasn't roused to respond though, maybe he was worried about the strength of the empire and thought discretion was the better option, given what had happened to his children in Meracydia.
He was there far enough back that the eggs of Bahamut and Tiamat could hatch, for them to mature enough to fly to Meracydia, start their own brood, and for that brood to spread and sire their own children until there were enough dragons later to summon Bahamut and for those dragons to be old enough that they gave rise to the diversity we can see in Azys Lla. All before Allag's invasion.

Why Middy broke the seal on Silvertear by willingly killing himself to stop the Garleans is probably going to be eternally unknown given his state after the events of Sigmascape(Or was it after Chaos? I can't remember.), but the power of the lake predates any known civilization. Who knows, maybe the Heart of Sabik is relevant and will finally be explained now that we're getting information on a pre-Sundering civilization.