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.

Developed using Pyrogenesis, a ground-breaking new game engine custom-built to suit our needs, 0 A.D. will give players a rich and entertaining real-time gaming experience. 0 A.D. is portable, running not only on Windows, like most games, but also on Linux and Mac OS X.

We believe free, OS software like 0 A.D. encourages sharing, learning and creativity. That's why we have made the code and data available under the GPL license, and released the art, sound and documentation under CC-BY-SA. Modifying the game's data files is as simple as editing JavaScript and XML files, so anyone can learn how the game was developed and share their own contribution to the 0 A.D. world.

0 A.D. has been in development by Wildfire Games (WFG), a group of volunteer, hobbyist game developers from all over the world, since 2001. We're currently working towards an alpha release of 0 A.D., after moving to open source development in July 2009. We're looking for programmers, 3d artists and more. Get involved.