Sid Meier's Civilization IV: Warlords is the first official expansion pack of the critically acclaimed turn-based strategy video game Civilization IV. Gameplay 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 leaders and civilization playable in single-player and multiplayer. Brennus (the Celts) Shaka (the Zulu) Ragnar (the Vikings) Hannibal (Carthage) Wang Kon (Korea) Mehmed II (the Ottomans) Four new leaders for existing civilizations. Stalin (Russia) Churchill (England) Ramesses II (Egypt) Augustus (Rome) 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. Inclusion of all patches released for original Civilization IV. The game introduces a new type of "Great Person" unit, known as a Great General. Great Generals are usually created when the total experience earned by a civilization's military units against other civilizations reaches specified thresholds, rather than Great Person points generated by its cities. In addition, the civilization that acquires the "Fascism" technology first receives a free Great General. A Great General can be used similarly to other Great Persons: to join a city as a "Great Military Instructor", which gives +2 experience points to any military unit created in the city, or to create a Military Academy, which permanently boosts military unit production (by +50%) in the city. The Great General can also be attached to a military unit forming a joint unit led by the Warlord, sharing 20 experience points with all units in its square and giving the Warlord unit free upgrades and exclusive access to special promotions. In all normal games and most scenarios, a destroyed Warlord unit is lost permanently. However, in the Alexander and Genghis Khan scenarios, the title characters serve as Great Generals, and if either is lost, he will be reborn in his civilization's capital city after several turns. The new Vassal States feature allows players to take up other empires as "vassals," the game's equivalent of protectorates. When an empire becomes a vassal, it loses the ability to declare war and make peace independently, and may be called upon to pay "tribute" in the form of game resources to its "master" (suzerain) state in return for the promise that its master will protect the vassal. Players can use Vassal States