Julius Caesar was so popular with the Roman people that the Senate named him dictator for life, but in 44BC, a group of senators stabbed Caesar to death. Caesar's primary lieutenant, Marc Antony became the ruler of Rome, but Caesar's will provided a surprise. Caesar ignored both Antony and Caesarion. Caesarion was Caesar's son with Cleopatra. The dictator instead named Octavian as his sole heir. Octavian was Caesar's eighteen year-old grandnephew An heir is someone who inherits a title or property. Caesar's will made Octavian one of the richest men in Rome, but the will provided Octavian with something even more valuable: the right for Octavian to call himself Caesar.
Octavian joined Antony and another general named Lepidus in an uneasy alliance known as the Second Triumvirate. Octavian and Antony forced Lepidus into retirement in 36BC. Octavian became the sole ruler of Rome with the death of Marc Antony five years later. Octavian ruled Rome for 41 years, a period when Rome developed into a military empire, so Octavian is considered by historians to be the first Roman Emperor. Octavian was careful not to meet the same fate as his great granduncle. He was very respectful to the senators, but the Senate knew that Octavian controlled the army and could do as he pleased.
Octavian took measures to earn the loyalty of the Roman army. He encouraged the soldiers to retire by providing them with land. Once the soldiers retired, Octavian did not have to be concerned with the army turning on him. Further, Octavian knew he could count on the retired soldiers' support if he was challenged by the Senate.
The Senate gave Octavian the title of Augustus in 27BC. Augustus means "the respected one." Octavian is usually referred to as Caesar Augustus after that date. Caesar Augustus restored peace and order to Rome after years of civil war. He made sure the lands throughout the empire were well run and taxes were fair. He built roads and bridges, government buildings, and huge public baths. He said, "I left Rome a city of marble, though I found it a city of bricks."
The armies of Caesar Augustus conquered most of Western Europe, North Africa and the Middle East. The Romans claimed all of the land surrounding the enormous Mediterranean Sea, which they called "a Roman lake." Rome developed into a great empire because of the strength and discipline of its army. The professionally trained Roman soldiers were divided into large units called legions. Each legion would have as many as 6,000 soldiers.
The Roman army was so powerful that it protected citizens from attack from the tribes who lived beyond the empire. Historian Edward Gibbon later described the two hundred-years of peace that began with the rule of Caesar Augustus as the Pax Romana, or the "Peace of Rome."