Xconq is a general strategy game system. It is a complete system that includes all the components: a portable engine, graphical interfaces for Unix/Linux/X11, Macintosh, and Windows, multiple AIs, networking for multi-player games, and an extensive game library.
In addition to Xconq’s “standard” game, which is similar to the classic Empire/Empire Deluxe games of years ago, the game library includes games for ancient civilizations, the Peloponnesian War, the Roman Civil War, Frederician strategy, Napoleonic strategy, Gettysburg at a brigade scale, the Russian revolution, the Normandy invasion, WWII at scales from tactical to grand strategic, Beirut street fighting, voyages of discovery, African exploration, and many others, including space and fantasy games.
Website & download: http://www.sourceware.org/xconq/