Age of Empires was generally well received, despite some highly negative reviews. GameSpot criticized a confused design, while Computer and Video Games praised the game as strong in single and multiplayer. The Academy of Interactive Arts & Sciences named Age of Empires the 1998 "Computer Strategy Game of the Year." For several years, the game remained high on the sales charts, with over three million units sold by 2000. The Rise of Rome was not as popular: it had only sold one million units in 2000, and attained 80% as an aggregate score from Game Rankings.
Age of Empires II: The Age of Kings, released on September 30, 1999, used the Genie game engine, and had gameplay similar to its predecessor. Age of Kings is set in the Middle Ages, from the Dark Ages to the Imperial Age. It allows players to choose one of 13 civilizations, from Europe, Asia, and the Middle East. Microsoft published the expansion, The Conquerors, on August 24, 2000. It added new units and five new civilizations, including two Mesoamerican civilizations; the Maya and the Aztec. The Age of Kings was a bigger critical success than the first two games, with Game Rankings and Metacritic scores of 92%. Microsoft shipped out more than two million copies to retailers, and the game received numerous awards and accolades. Critics agreed that The Conquerors expanded well on The Age of Kings, though issues of unbalanced gameplay were raised. The Age of Kings and The Conquerors won the 2000 and 2001 "Computer Strategy Game of the Year" awards from the Academy of Interactive Arts & Sciences, respectively.
Age of Empires III, released on October 18, 2005, was built on an improved version of the Age of Mythology game engine with the most significant changes being the updated graphics engine and the inclusion of the Havok physics middleware engine. The game is set in the period between 1421 and 1850, and players can choose one of eight European nations. The game introduced a large number of features, such as home cities. Described by Ensemble Studios as "an important support system to your efforts in the New World," home cities helped provide the player with resources, equipment, troops, and upgrades. They could be used across multiple games, and upgraded after each battle; it was compared to a role-playing game character by Ensemble Studios. The first expansion to Age of Empires III, The WarChiefs, was released October 17, 2006. Most gameplay changes in the expansion pack were small, but it introduced three new civilizations, with a focus on Native Americans. Most notable was the introduction of the WarChief unit. The second expansion, The Asian Dynasties, went on sale October 23, 2007. It was a jointly developed