Simplify the following text for a Grade 8 native English-speaking person.
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 . Age of Empires III has sold over 2 million copies as of May 2008 .
Simplified: An expansion pack , Age of Empires III : The WarChiefs , was released for the game on October 19 , 2006 .