By winning the Battle of Alesia, the brilliant military tactician and politician Gaius Julius Caesar subdues the last of the Roman Republic's invaders. Then he takes control of the government, and spawns a civil war. The opposition is led by Pompey the Great, fighting on the side of the majority of the Senate. Caesar is victorious and declares himself emperor, diminishing the power of the Senate and establishing a royal line of ascension.

The burning of Rome signals the onset of Emperor Nero Claudius Caesar's descent into madness. As plans to build a much grander capital city threaten the empire with bankruptcy, Nero resorts to increasingly bloodthirsty ways to raise money. After he orders wealthy citizens murdered for their money, the Senate declares him an enemy of the state.

Constantine takes control of the divided empire one emperor at a time. After defeating one of the triumvirate, he marries his sister to another. Together, they take on the third emperor. Then there were two. After publicly declaring that the pagan Rome be united under one religion and one emperor, Constantine defeats his brother-in-law and establishes Christianity as a valid religion.