Augustus (plural Augusti; /ɔːˈɡʌstəs/ aw-GUST-əs,[1] Classical Latin: [au̯ˈɡʊstʊs]; "majestic", "great" or "venerable") was the main title of the Roman emperors during Antiquity.
[2][3][4] It was given as both name and title to Gaius Julius Caesar Octavianus (often referred to simply as Augustus) in 27 BC, marking his accession as Rome's first emperor.
In Rome's Greek-speaking provinces, "Augustus" was translated as Sebastos (Σεβαστός), or Hellenised as Augoustos (Αὔγουστος); these titles continued to be used in the Byzantine Empire until the Fall of Constantinople in 1453, although they gradually lost their imperial exclusivity in favour of Basileus and Autokrator.
He was the grand-nephew and later posthumously adopted as the son and heir of Julius Caesar, who had been murdered for his seeming aspiration to divine monarchy, then subsequently and officially deified.
Octavian studiously avoided any association with Caesar's claims, other than acknowledging his position and duties as Divi filius ("son of the deified one").
He had ended Rome's prolonged and bloody civil war with his victory at Actium, and established a lasting peace.
[10] So his official renaming in a form vaguely associated with a traditionally Republican religiosity, but unprecedented as a cognomen, may have served to show that he owed his position to the approval of Rome and its gods, and possibly his own unique, elevated, "godlike" nature and talents.
The religious ambiguity of the title allowed for this kind of deification throughout the empire as subjects – beginning from Asia and Bithynia – adopted the worship of the genius or soul of Augustus, establishing a ruler-cult.
[4] Beginning with Valentinian the Great and his brother Valens, whom he raised to Augustus pari iure, 'Augustus without reserve' in 364, the concurrent Augusti of the eastern and western provinces were of equal standing.
[4] Until Heraclius's 629 reforms, royal titles had been eschewed in Rome since the legendary overthrow of the Roman monarchy's last king Tarquinius Superbus by Lucius Junius Brutus in the late 6th century BC.
[4] The Imperial titles of imperator, caesar, and augustus were respectively rendered in Greek as autokratōr, kaisar, and augoustos (or sebastos[13]).
The relative simplicity of the style and absence of any mention of Rome was in deference to Byzantium (although he would briefly use the title imperator Augustus Romanorum ac Francorum (Emperor-Augustus of the Romans and Franks) in 966), which would soon reach the medieval apex of its power.