Untold millennia ago, groups of pilgrims settled in the greater Atlantean region establishing twelve distinctive communities, a few of which evolved into the city-states now known as Poseidonis and Tritonis. While they had survived, the citizens of Poseidonis could no longer leave their city due to the depths surrounding them outside the dome. Shalako, brother to the city's monarch, King Orin, used his magic to protect his followers from the crushing pressure of the ocean depths, and they migrated from Poseidonis and re-established a colony in the ruins of the sister-city Tritonis.