the Augustus

Augustus, the (Gk. sebastos, ‘reverend’), title held exclusively by all the Roman emperors except Vitellius. When the emperor Diocletian established a tetrarchy by dividing the empire among four rulers in AD 293, he established two nominally joint emperors who shared the title of Augustus to rule the eastern and western halves of the empire, each with a subordinate ruler, designated a Caesar, who might expect to succeed to the higher rank. By personal authority the senior Augustus could hope to remain in effect sole emperor. Although the system failed as a means of establishing the succession, the titles and their general application survived. The title ‘Augusta’ was bequeathed by the emperor Augustus to his wife Livia, and after Domitian was held by the wife of the reigning emperor.