I'm having trouble figuring out a way to turn animosity between two religious factions into a full-out war.
Currently, there are two, the Brotherhood and the Pale. They believe in opposing Gods, have opposing traditions, etc. The Brotherhood is significantly larger, richer, and more powerful than the Pale, and currently manipulate the Emperor sitting on the throne.
What are events that would cause the Brotherhood to simply outlaw the Pale, or call for a crusade/genocide of anybody not within the Brotherhood? For a while I was thinking serial murders would be a good idea, until I realized that murders are a cause for arrest and execution, not the wide-scale conflict I'm searching for. I figured perhaps history had some precedent?
Thanks so much!