AUGUSTUS (63 BCE–14 CE), Roman emperor. Born Gaius Octavius, he was the grandnephew of Julius Caesar. Adopted by Caesar, and made his chief heir at nineteen, Octavius built upon Caesar's name, charisma, military success, political connections, and fortune. Calculating, opportunistic, an unfailingly shrewd judge of men and circumstances, he emerged in 31 BCE from thirteen years of political chaos and civil war triumphant over Mark Antony and sole master of the Roman world.

Exhausted by the effects of civil war and seeking only peace and a return of order and prosperity, Roman citizens and provincial subjects alike hailed Octavius as a savior sent by divine Providence. He did not fall short of their expectations. To mark the beginning of a new order, he assumed the name Augustus in 27 BCE. In a series of gradual steps, he restructured the Roman political system. While preserving the forms of republican government, he in...