Original: Two expansion packs have been released: the first, Age of Empires III: The WarChiefs, was released on October 17, 2006, and introduced three Native American civilizations; the second, Age of Empires III: The Asian Dynasties, was released on October 23, 2007, and included three Asian civilizations.
Simplified: An expansion pack, Age of Empires III: The WarChiefs, was released for the game on October 19, 2006.