Era beginning/end
The year that the Celestials finally won over Vox from the Ancients.
The contents of the battle had been vague, in some history text it says the Ancients faded from this world, leaving their kin to gather what was left of them and start anew, but in a buried underground temple (In the Mountain where the Fallen Fotress now resides) there is a text of how the Celestials had fought for their freedom on the plains where Esmengard now sits. It is also said that the Celestial gained their divine powers for their mercy to not kill and the curse of the Kiriyuu's (that if they have twins one will devour the other) was placed by the Ancients.