Civilization IV: Warlords

Warlords added many new features to the original game. These include: A new category of Great People known as "Great Generals". The ability to institute vassal states. Eight new scenarios. Six new civilizations playable in single-player and multiplayer. Ten new leaders... Three new leader traits (Charismatic, Protective and Imperialistic). Unique buildings for each civilization. Three new wonders. New units, resources, and improvements. Core gameplay tweaks and additions. (wikipedia.org)