This is the war started by a Galactic Alliance assault on the Ni'novian Empire in the first month of 45 ABY. The name "Galaxial War" was selected by the Sith Council to name the war. Note, the Jedi and the Galactic Alliance may refer to this by a different name. In the first days of the War, the Sith were reeling by the surprise assault and the influences of the traitor, Nexus. After a month, the Sith Council exposed Nexus and executed him. After that, they officially declared war on the Galactic Alliance.