General War
In the fictional Star Fleet Universe as represented in the range of games from Amarillo Design Bureau as well as the first two Star Fleet Command games (and the Orion Pirates stand-alone addon for Starfleet Command II) from Taldren, the General War was an 18-year conflict waged between various empires, with the Coalition of the Klingon Empire, the Lyran Star Empire and eventually the Romulan Star Empire at war with the Alliance of initially the Kzinti Hegemony (Mirak Star League in Starfleet Command) and the Hydran Kingdoms, eventually including the United Federation of Planets, the Gorn Confederation and the Tholian Holdfast (the Tholians are not represented in Starfleet Command).
A summary of the General War exists at http://www.starfleetgames.com/sfb/sfin/general_war.htm