Suetonius traces the history of Augustus’s paternal family, the Octavii, back to the days before the Roman Republic, although the family did not achieve senatorial rank until the days of Augustus’s father. Suetonius adds that Mark Antony accused Augustus of having an ex-slave as a great-grandfather and a grandfather who was a financial agent, but Suetonius could not disprove or verify these allegations.

Octavian’s father died when he was four years old, and he was named the heir of his great-uncle Julius Caesar. After Caesar’s assassination, he and Mark Antony fought against the assassins and their supporters. Over time, Octavian’s alliance with Mark Antony fell apart, especially once Mark Antony joined Queen Cleopatra in Egypt. Octavian and Mark Antony’s conflict began a new civil war that ended when Octavian defeated Cleopatra and Mark Antony’s navy at the Battle of Actium. Antony and Cleopatra committed suicide, and Octavian annexed the kingdom of Egypt to the empire and claimed undisputed mastery of the Roman government.

Octavian expanded Roman rule into parts of what is now southwestern France, northeastern Spain, and the Balkans. Suetonius argues that he only experienced two military defeats in his lifetime, the worst of which was when the general Varus lost three legions in Germany.