All Under Heaven takes the game and transforms it into a Medieval Asian setting, in a period on the eve of the Mongol invasions of Asia, where the entire continent is about to be thrown into a period of warfare which will shape its history and determine the autonomy of many sovereign nations. In All Under Heaven, you may choose to control one of 15 nations from the start date of 1180 A.D. to the end date of 1280 A.D. Hundreds of new units, buildings, events, traits, ancillaries, and other features will bring the mystique and splendor of the Far East into your home.
This picture shows an example of the war/peace party system of the Song Dynasty. At the time of the mod the court was strongly divided along these lines, and that will be reflected in the mod with bonuses/penalties for different factionwide affiliations.