Sid Meier's Civilization IV: Warlords

Sid Meier's Civilization IV: Warlords is the first official expansion pack released for Civilization IV, the acclaimed turn-based strategy game.

Among other developments, this expansion includes 6 new civilizations, 10 new leaders of civilizations, 8 new scenarios and new units and buildings. Warlords adds several new features and improvements to the original game. The most important are:
- A new category of "Great People", Great Generals. - Now civilizations can have vassal states. - Eight new scenarios. - Six new civilizations playable. One player mode or Multiplayer mode. - Ten new leaders of civilization (including 4 new leaders for existing civilizations). - Three new features of the leaders (Charismatic, and Imperial Guard). - Now every civilization has a unique building, available only for that civilization. - Three new wonders of the world. - New units, resources and improvements to the ground. - Improvements and additions to the system of play.
Although there are some other changes, the essential are two: Great Generals and the possibility of having vassal states.

Great Generals: They can be obtained in 2 ways: by getting experience points in the battles of your troops against those of another civilization (you do not earn points if you fight barbarians or animals) or investigating the technology Fascism before another civilization investigates it first. A Great General can be used to start a Golden Age. The Great Generals can also lead a military unit.

Vassals States: With the new concept of vassalage that this expansion has introduced, players can now absorb small states to have them as vassals. A Vassal State can not declare war under any circumstances.

Regarding graphics, it does not include significant changes and it remains still in the same line of the original. The title also includes several updates and patches which appeared for the original version and are installed with this expansion.