User blog comment:Octofan/Original Sin Story -Act 2- Booklet/@comment-12148883-20130910192204/@comment-6192846-20130910201719

The only thing I see that could possibly distinguish the eras is when their calendar system was redone, marking the first year for the EC (the E may even stand for era). If so, then the legacy of the second era was basically everything the Magic Kingdom had accomplish up till the twin's births. I don't see a mention in any of the novels of any eras though.