Have you made any attempt at making a timeline for he settlement and conquest of the various Anuirean colonies in Aduria? From the setting material it is the period 700 HC to 800 HC that marks the height of the Empire. If the colonies were to have a significant amount of time to be settled and to prosper the first expeditions should perhaps have taken place a few centuries earlier. With the majority of Cerilia subjugated relatively early on, there should have been ample time and resources to this venture even in the earlier centuries after the Empire's formation.

Cheers,
E