In a decisive naval battle in the Ionian Sea, Octavian's admiral Marcus Agrippa outmaneuvered the larger, more cumbersome ships of Antony and Cleopatra's fleet. Cleopatra's squadron broke and fled partway through the engagement, and Antony followed, abandoning much of his force. The victory left Octavian unchallenged, and within a year both Antony and Cleopatra were dead, Egypt became a Roman province, and Octavian began his transformation into Augustus, Rome's first emperor.
Antony's ships were heavier, built for ramming, but Agrippa's lighter, more agile vessels ran circles around them, using fire arrows and superior maneuverability to devastating effect. When Cleopatra's sixty ships suddenly hoisted sail and slipped through the battle line, some historians have debated whether it was a planned retreat or panicked flight—but Antony's decision to abandon his fleet and follow her aboard a smaller vessel sealed his fate.
The battle effectively ended the century of civil wars that had convulsed the Roman Republic since the days of Marius and Sulla. Octavian's consolidation of power afterward, cloaked carefully in Republican language even as he accumulated absolute authority, inaugurated the Pax Romana and two centuries of comparative stability across the Mediterranean world under imperial rule.
Key people: Octavian, Mark Antony, Cleopatra, Marcus Agrippa