War of Actium: Octavian defeated the forces of Mark Antony and Cleopatra at Alexandria, establishing Roman Egypt. Augustus: Augustus, also known as Octavian, 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 when the Roman world was largely free of armed conflict. The principate, a style of government in which the emperor showed nominal deference to the Senate, was established during his reign and lasted until the Crisis of the Third Century. August 1, 30 BC. Wiki link