Augustus, also known as Octavian (Latin: Octavianus), was the founder of the Roman Empire and the first Roman emperor from 27 BC until his death in AD 14. The reign of Augustus initiated an imperial cult and an era of imperial peace (the Pax Romana or Pax Augusta) in which the Roman world was largely free of armed conflict. The principate, a style of government where the emperor showed nominal deference to the Senate, was established during his reign and lasted until the Crisis of the Third Century.
Octavian was born into an equestrian branch of the plebeian gens Octavia. After his great-uncle, the dictator Julius Caesar, was assassinated in 44 BC, Octavian, whom Caesar named as his primary heir in his will, inherited Caesar's estate and assumed his name. He fought for the loyalty of Caesar's legions. He was made a senator during a state emergency and seized power by marching on Rome in 43 BC, becoming its youngest elected consul. He, Mark Antony, and Marcus Lepidus formed a triumvirate regime with legally sanctioned powers to outlaw and oppose the assassins of Caesar and their allies.