Including a new great person type called the Warlord you will be able to conquer an enemy and subjugate them to your rule as Vassal States.
The expansion will deliver six scenarios and 6 new civilizations and associated unique units. Ten new leaders will be also be provided and the list will include leaders for the new civilizations as well as additional leaders for existing civilizations.
Each civilization will have a new unique building as well as their unique unit and many new items will be presented throughout the scenarios. Expanded features and gameplay tweaks will be made to the core game giving unprecedented control throughout. The pack will also contain all of the patches and game additions (pit boss, etc.) yet released for Sid Meier's Civilization IV.

New Scenario List
Chinese Unification (350 BC): Take control of one of Ancient China’s kingdoms in an attempt to unify the country by either the pen or the sword.
Peloponnesian Wars (430 BC): Mighty Athens and Sparta struggle for dominance of Greece and surrounding territories.
Alexander’s Conquests (330 BC): Alexander attempts to conquer the world to the south and east of Greece, taking on the Persians, Egyptians, and Indians.
Rise of Rome (300 BC): Battle as Rome, Carthage, Greece, Gaul, or Egypt for control of the Mediterranean.
Vikings (800 AD): Become ruler of the Vikings and send your men out on numerous raids against Europe. Victory is decided by how much loot can be acquired.
Genghis Khan (1206 AD): Relive the conquests of one of history’s greatest military leaders and capture – or if you must, destroy – all of Asia.