Augustus
Augustus' reign laid the foundations of a regime that lasted, in one form or another, for nearly fifteen hundred years through the ultimate decline of the Western Roman Empire and until the Fall of Constantinople in 1453. Both his adoptive surname, Caesar, and his title "Augustus" became the permanent titles of the rulers of the Roman Empire for fourteen centuries after his death, in use both at Old Rome and at New Rome. In many languages, "Caesar" became the word for "Emperor", as in the German "Kaiser" and in the Bulgarian and subsequently Russian "Tsar" (sometimes Csar or Czar). The cult of "Divus Augustus" continued until the state religion of the Empire was changed to Christianity in 391 by Theodosius I. Consequently, there are many excellent statues and busts of the first emperor. He had composed an account of his achievements, the "Res Gestae Divi Augusti", to be inscribed in bronze in front of his mausoleum. Copies of the text were inscribed throughout the Empire upon his death. The inscriptions in Latin featured translations in Greek beside it, and were inscribed on many public edifices, such as the temple in Ankara dubbed the "Monumentum Ancyranum", called the "queen of inscriptions" by historian Theodor Mommsen.
Julius Caesar
Because Caesar's clemency had resulted in his murder, the Second Triumvirate reinstated the practice of proscription, abandoned since Sulla. It engaged in the legally sanctioned killing of a large number of its opponents to secure funding for its 45 legions in the second civil war against Brutus and Cassius. Antony and Octavian defeated them at Philippi.
Afterward, Mark Antony formed an alliance with Caesar's lover, Cleopatra, intending to use the fabulously wealthy Egypt as a base to dominate Rome. A third civil war broke out between Octavian on one hand and Antony and Cleopatra on the other. This final civil war, culminating in the latter's defeat at Actium in 31 BC and suicide in Egypt in 30 BC, resulted in the permanent ascendancy of Octavian, who became the first Roman emperor, under the name Caesar Augustus, a name conveying religious, rather than political, authority.