Middle Sea: Empires of the Feudal Age (1979)

A multi-player† board game that recreates the growth of empires during the Middle Ages throughout the Mediterranean world. Christians and Moslems in conflict among themselves and with each other.

Originally a PBM game; it involves partially hidden movement (you move "armies" and "fleets" of hidden make-up) as well as simultaneous turn plotting. Spy rings are valuable intelligence-gathering units. Areas fought over repeatedly suffer from the warfare and have their economic value depressed --a neat touch which is unfortunately uncommon in wargames.

† In theory, the game can accommodate 40 players, one for each leader and its province.