Octavian united Rome and defeated Julius Caesar's killers. For this, the Senate rewarded him with the title of "Augustus" or "revered one." This marked the end of the Republic and the beginning of the Roman Empire, because the Senate gave all of its authority to Octavian. Octavian became the first Roman emperor, and he was known as Caesar Augustus from then on. 

Caesar Augustus thought that if he encouraged people to be more interested in values such as simplicity, hard work, patriotism, and religion, they would become more virtuous, which would help the entire empire. He repaired many of the old temples, and built new ones. He encouraged science, art, and literature, built new roads, and created fair taxes.

Augustus also reorganized the government into a system that worked well for hundreds of years. As emperor, he kept all real power for himself, but he often consulted with the Senate. He set up branches of government in all the different areas of the empire, giving the governors just enough power to feel useful, but not enough to take their own control. He started the first firefighting service and the first public police. He was a good ruler from 27 B.C. to 14 A.D., when he died.

Under the Roman Empire, the Roman people lived in peace for 200 years. This period was called the “Pax Romana.”