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, resulted in the permanent ascendancy of Octavian, who became the first Roman emperor, under the name Caesar Augustus, a name that raised him to the status of a deity.
The Battle of Actium was the decisive confrontation of the Final War of the Roman Republic, a naval engagement between Octavian and the combined forces of Mark Antony and Cleopatra on 2 September 31 BC, on the Ionian Sea near the promontory of Actium, in the Roman province of Epirus Vetus in Greece. Octavian's fleet was commanded by Marcus Vipsanius Agrippa, while Antony's fleet was supported by the power of Queen Cleopatra of Ptolemaic Egypt.