Supreme Ruler Plus

Supreme Ruler Plus is an updated and expanded version of the October 1982 release Supreme Ruler. The players each control a region's government and attempt to conquer a fictional world of fragmented states. The game simulates raising funds through taxes and spending on agriculture, government services, and the military. Up to 9 regions play at once, either human hotseat or AI controlled, and all actions are resolved simultaneously at the end of each turn. The design of Supreme Ruler was influenced by earlier nation-state simulations such as Sumer, though the concept is taken further with the addition of multiplayer, military battles, and a more sophisticated design.

Source: Wikipedia, "Supreme Ruler", available under the CC-BY-SA License.