Which decisive naval battle ended Antony and Cleopatra's power and left Octavian as the sole ruler?

• A. The Battle of Philippi
• B. The Battle of Actium
• C. The Battle of Pharsalus
• D. The Battle of Zama

Answer: (B)

Naval supremacy decides political fate in the late Republic. The decisive clash off Actium in 31 BCE pitted Octavian’s fleet, commanded by Agrippa, against Antony and Cleopatra’s forces. Octavian’s victory shattered Antony and Cleopatra’s ability to wield power at sea, and their leadership quickly collapsed—their forces dispersed, and Antony died by his own hand with Cleopatra following soon after. This defeat left Octavian as the sole ruler, soon after taking the title of Augustus and inaugurating the imperial era. The other battles mentioned come from different contexts: Philippi was a land engagement that sealed the fortunes of Caesar’s party in the civil wars, Pharsalus was Caesar’s victory on land over Pompey, and Zama was Hannibal’s defeat long before these events. Actium stands out as the naval turning point that ends Antony and Cleopatra’s power.