The Prizm Wars were fought roughly ten millennia ago, when Gaeleth was first plucked from its orbit about Maroth and thrust into orbit about a star in a distant system. The Prizm Wars were, for many, just a continuation of the Sister Worlds War which had raged on for some time. Gaeleth was getting hammered during the Sister Worlds War, and several of its mages sought to protect their world from harm by moving it to another star, if only for awhile. The movement and the creation of the Shield to prevent teleportations and travel to Gaeleth, sent the land into significant turmoil. None of the mages involved anticipated the gravitic whiplash that would occur, and Gaeleth itself went into considerable turmoil as earthquakes spawned tsunamis, volcanoes, and choking atmospheric gases. It took centuries of work by the gods and the greatest of the mages and priests to contain the problem, but not before most of the knowledge of how to undo it – and knowledge of the Sister Worlds War itself – was nearly wiped out.
For a more complete story, see the Master Plan.