The One Sith causes the destruction of the peace

The Fel Empire seized on the opportunity opened by the loss of confidence in the Galactic Alliance. With the Pellaeon–Gavrisom Treaty that ended its war against the former Rebellion came in 19 ABY, the Imperial Remnant had ended its hostilities to the New Republic as a neutral faction, and the Yuuzhan Vong invasion had brought them together as allies to the New Republic and its successor. But its nominal government, the members of the Moff Council, still had many hard-line holdovers to the old ways who wanted to restore the Empire to primacy as the dominant galactic power, peace treaty or not. Now they called for retribution and, invoking the Treaty of Anaxes, they declared war on the Galactic Alliance. The peace that so many had fought and died for in decades past was undone in one swift stroke, all thanks to the resurgent Sith Order.