Dormian Sundering
The Dormian Sundering was a civil war occurring in Dormia from 94 AO until 98 AO, which ultimately resulted in the splitting up of Dormia into the Kingdom of Vesper in the west and the Auroran Republic in the east.
When the original settlers landed, they viewed magic as simply a tool to help achieve their goals, much the same as technology, The Dragon War changed all that, when they saw first hand the wanton destruction that extremely powerful magic can cause. After the dragon Nileraxxemon was killed and his army disbanded, the human armies journeyed back through the Magna Mountains and settled the city of Riverlake. It was from here that the entire land was ruled, and the first order of business was to ban magic across the kingdom.
Those who remained in the east were mostly the folks who were unable to contribute to the war: women, children, and the elderly. Not seeing much of the destruction first hand, many of them did not take offense to the continued utilization of magic. The elderly, many of whom had a good mastery of the arcane at this point, continued to use it and to teach the children and women how to do the same. Instead of seeing its folly, they instead celebrated magic's virtue, and did not agree with the ban on magic. In fact, many of the practitioners ignored the ban altogether and continued wielding the arcane.
This act of defiance enraged the First King, Harrison Bartram, who had a vision of a world free from the Arcane and free from the kind of mass destruction he knew it could cause, He immediately began cracking down on arcane users, sending soldiers from the west to police the east and ensure nobody was using magic. The first soldiers arrived in the year 92, and the plan world for a time. The first riots began in late 93 AO, with a full blown civil war breaking out in the fall of 94 AO.
The war itself dragged on for 3 years of practical stalemates. The people of the east refrained from using destructive magic to win the war, because doing so would contribute to proving Harrison's point. However, after 3 years of suffering and many casualties on both sides, the leader of the People's Army, Mathieu Deregimber, made a difficult decision. He decided to permit all wizards of the east to use destructive magic against the assailants. The war ended within 6 months, in the winter of 98 AO.
Not wanting complete control over the resentful and vindictive westerners, now referred to as the Vesperans, Mathieu met with King Harrison and the two agreed to a truce, allowing Harrison to retain control over the lands west of the the Sea of Horses and Mathieu would control the lands to the east. The sea itself would remain neutral territory.
The Arcane Ban was lifted, though magic still had a very negative connotation in the Kingdom of Vesper, and many of its citizens refused to use it, viewing it as a crutch for the weak. In the east, magic was still widely used by the Aurorans and thrived.