0 A.D. is a free, open-source, real-time strategy (RTS) game of ancient warfare. It's a historically-based war/economy game that allows players to relive or rewrite the history of ancient civilizations, each depicted at their peak of economic growth and military prowess.
Lead a civilization, develop a thriving city, raise a mighty army and contend with rivals for hegemony of the world. History is yours for the taking!
More information about the game and Mac and Linux versions can be found on Wildfire Games' site.
Note: This game is still in development, bugs and missing features are to be expected at this stage. You will gain access to the latest stable build and receive the full game once it is complete.