0 A.D. is a 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 twelve ancient civilizations, each depicted at their peak of economic growth and military prowess.

The twelve factions are: Three of the Hellenic States (Athens, Sparta and Macedonia), two of the kingdoms of Alexander the Great's successors (Seleucids and Ptolemaic Egyptians), two Celtic tribes (Britons and Gauls), the Romans, the Persians, the Iberians, the Carthaginians, and the Mauryans. Each civilization is complete with substantially unique artwork, technologies and civilization bonuses.