Chronicle of the Coda Reborn
The First Age is also known as the Age of Heroes. During this age the first races came into civilization and history as we know it began. The First Age thus occurred directly after the Age of Forming when Ahm, Ehm, and Ohm formed the world.
This age ends with the revolt of Aiden against the gods and his subsequent dismissal from this reality. The gods retreated to Celestia and agreed to not interfere directly on the Plane of Tomoresse ever again.