2 September 31 BCE

The victory won at Actium off the coast of Greece by Julius Caesar’s adopted son, Gaius Julius Caesar Octavianus (better known as Octavian, and soon to become Augustus) marked a decisive end to the long period of savage civil wars that had plagued Republican Rome from the middle years of the first century BCE. The battle was fought between the two most powerful men in the Roman Republic: Octavian, ruler of the western half of the Roman territories; and Marcus Antonius (better known as Mark Antony), ruler of the eastern region. Octavian had little reputation as a commander or soldier, but from an early age he had understood how to balance the arts of politics and war. Mark Antony was out-thought by a leader whose political intelligence and strategic calculation opened the way to a new imperial age.

This painting of Antony and Cleopatra at the Battle of Actium (31 BCE) was made by the Austrian rococo painter Johann Georg Platzer (1704-61), famous for his historical and allegorical subjects. In reality, during the battle that ended the Roman Civil War, Cleopatra stayed back from the conflict until there was room for her vessels to escape into the open sea.

After the assassination of Julius Caesar in 44 BCE, there followed an uneasy decade as Caesar’s supporters fought against the defenders of Republican Rome and rival claimants to his mantle. Octavian became the dominant figure in Italy because he was more clear-sighted and unscrupulous than his competitors. Though he had no constitutional basis for his claim to rule, he was backed by soldiers loyal to the legacy of the great Caesar, and had enough money to buy the loyalty of others. He collaborated with Antony for much of the decade, and relied on Antony’s military help against the armies raised by Caesar’s assassins. But by 34 BCE, when Antony married the Egyptian queen Cleopatra in a theatrical ceremony in Alexandria, Octavian could see the possibility that Mark Antony might soon want control of the whole Roman sphere and not just the east. By 32 BCE, their rivalry was overt. One-third of the Senate in Rome supported Mark Antony and fled to join his army, which was gathering in Turkey; Octavian had been busy recruiting supporters in Italy, raising taxes for a military expedition, buying the loyalty of his own troops and spreading hostile propaganda against his rival. Ambition turned both heads as the two men contemplated the prospect of ruling the whole Roman world.

In the second half of the year, Antony brought an army of around 100,000 soldiers and 12,000 cavalry to Greece, supported by 500 ships, many of them huge triremes capable of carrying large numbers of soldiers and catapults to be used while ramming and boarding enemy vessels. The object was to prepare for an invasion of Italy, or to lure Octavian into a land battle, which Antony was confident of winning. The fleet was scattered along the coastal ports, but around 250 ships were concentrated in the Gulf of Ambracia, a bay on the west coast of Greece protected by a narrow strait near the town of Actium. They included sixty vessels supplied by Cleopatra, who had accompanied her new consort to witness his triumphant return to Rome. Octavian knew that he had time on his side and decided to blockade Antony. His own fleet, commanded by the very effective Marcus Vipsanius Agrippa, preyed on Antony’s supply routes. Octavian moved his army of around 80,000 legionaries and 12,000 horsemen to Greece and set up camp well to the north in order to avoid a land battle, while the fleet of Antony and Cleopatra remained bottled up at Actium, unwilling to risk a major sea battle against the larger naval forces waiting beyond the Gulf.

In this trial of wills, Octavian understood that Antony’s expeditionary force could only decline in fighting power as it struggled to find food and fodder locally and to cope with camp diseases. There were defections to Octavian as morale declined. Antony’s decision to base himself at Actium had been a mistake, but Octavian exploited this misjudgement to the full by avoiding a pitched battle and relying on attrition. Unable to bring his strength to bear against an evasive enemy, Antony decided that his only option was to try to break out of the Gulf and fight his way through Agrippa’s blockade. He concealed his intention from his already demoralized army and when a strong northwest wind arrived on 2 September 31 BCE, Antony ordered his fleet, now reduced to no more than 170 vessels, out of the Gulf and into the open sea.

The four-hour battle that followed was directed by Octavian, who was aboard a small brigantine (suffering, it has been suggested, from sea-sickness), but fought by his admiral, Agrippa. The long delay and the strategy of blockade both played to Octavian’s advantage. Antony’s ships did not seek battle, but were equipped with sails and masts for a break-out. The decks of his ships were cluttered with stores and 20,000 marines, who were embarked with the fleet. His oarsmen were hungry and disease-ridden and no match now for Agrippa’s 400 faster and lighter ships, but they were forced to fight rather than flee. As Antony’s three squadrons came out of the gulf they formed into a crescent, with a fourth squadron of Cleopatra’s sixty ships behind them, prepared with full sail and carrying the treasure needed to fund the war. Agrippa was ready for them. His right squadron engaged with Mark Antony’s left at once, coming to close quarters and using marines to devastate and board the enemy vessels.

As Mark Antony’s right tried to manoeuvre around Agrippa’s fleet, the latter moved his ships further north to envelop the enemy, until the two wings became separated from the rest of the battle. As the centre opened up, Cleopatra seized her moment to sail between the two fighting wings out into the open sea. Mark Antony and some of his vessels on the right then followed them, but sensing that his flagship was too slow, he transferred to a lighter and faster vessel and caught up with Cleopatra, leaving his fleet and his army to their fate.

That fate was harsh indeed. At least two-thirds of the fleet was captured after several hours of fierce fighting and perhaps 10,000 men killed, some of them, according to ancient accounts, ‘mangled by sea monsters’. Much of the army came over to Octavian and those who fled the scene surrendered not long after in Macedonia. The victory at Actium owed something to the mistakes of Antony and Cleopatra, but much to the strategic understanding of Octavian, who, though he lacked the hero’s touch, understood that a battle could be won by patient waiting and the fruits of calculated attrition. The following year, Octavian pursued Antony and Cleopatra to Egypt, captured Alexandria and shared its treasures with his army. Mark Antony stabbed himself and perished in Cleopatra’s arms; she died nine days later once it was clear no deal could be struck with Octavian, reputedly from the bites of twin asps. Gaius Octavianus returned in triumph to Rome in 29 BCE and was declared ‘Augustus’ by the Senate two years later, de facto ruler of the Roman Empire. A holiday was proclaimed to mark the victory in Egypt, still celebrated in Italy two millennia later as ‘Ferragosto’.