0 A.D. (pronounced "zero ey-dee") is a free, open-source, cross-platform 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 six ancient Western civilizations, each depicted at their peak of economic growth and military prowess. The six factions are: The Hellenic States (aka The Greeks), the Roman Republic, The Celtic Tribes, the Persian Empire, the Iberian Tribes, and the Carthaginian Empire, each complete with unique artwork, technologies and civilisation bonuses.
