*Gosh I hope this hasn't been asked before*

While waiting for this game I got really absorbed into the lore and now want to know more about the first Umbral eras. We all know that our favorite bad guy ushered in the 7th Umbral Era with Dalamud and we will be in the 7th Umbral Era when we start ARR. However, how did the first 6 Umbral Eras start? Is there any information out there that would give specifics about these earlier Umbral Eras? I know the first six were all related to specific elements but that much is still pretty vague.