The remainder of the army, totaling about fifty thousand men, was under the command of Publius Canidius Crassus, a long-standing partisan of Antony who had campaigned with great success in Armenia. If the fleet managed to make a getaway, he was to march to Macedonia, if possible, and then the east.
Before setting off, Antony gave his ships’ captains the unusual order to take their sails with them, claiming this would help to ensure that not a single enemy ship escaped capture. Sails were seldom if ever used in battle (they took up too much room when stowed and reduced maneuverability when set); his men, seeing through Antony’s flimsy rationale, realized with dismay that he was not confident of victory, indeed that he anticipated flight.
Dellius had briefed Agrippa about Antony’s arrangements, including the decision to load the sails. Also, the men from the two armies who were not with the fleets lined the shores to watch events at sea. Octavian’s soldiers were able to see exactly what Antony was doing in the strait and may very well have kept their commanders informed, by small boat or some form of signaling.
As anticipated, the ships emerged from the strait, rowing in file, and deployed in two lines that stretched between the headlands. There they halted. Cleopatra’s squadron hung behind the lines, and did not look as if it was going to play an active part in the battle.
Antony waited hopefully for the enemy to accept the bait, sail toward the opening of the strait, and give battle. The ploy failed, for Agrippa sensibly refused to move. A very long pause followed that lasted all morning. The two fleets, perhaps a mile apart, rested on their oars.
Agrippa waited for Antony to accept that his bluff had been called, move his ships forward, and leave the comparative safety of the strait for the open sea. This he eventually did, stationing himself with the squadron on the right. The command of his left wing was given to the competent Sosius.
At this point our sources are blinded by the fog of battle and we have only the broadest and vaguest view of what happened. Plutarch gives a good general impression:
The fighting took on much of the character of a land battle, or, to be more exact, of an attack on a fortified town. Three or four of Octavian’s ships clustered around each one of Antony’s and the fighting was carried on with wicker shields, spears, poles, and flaming missiles, while Antony’s soldiers also shot with catapults from wooden towers.
Having a greater number of war galleys, Agrippa could draw up his fleet in two lines, and probably did so, while Antony was restricted to one. Fairly early in the engagement, Agrippa began to feel his way around the enemy’s northern flank. Antony’s ships responded by edging northward themselves, perhaps swinging around from a north/south to a west/east axis. This had the effect of weakening Antony’s center, and to a lesser extent Agrippa’s.
The battle had been going on for a couple of hours. Although Antony’s ships were putting up a good fight, Agrippa must have been feeling well pleased. There was no way the enemy line would be able to break through.
Then an astonishing thing occurred. In the early afternoon, the wind shifted (as it regularly did every day) toward the north. Cleopatra’s squadron, lurking in the background and taking no part in the fighting, suddenly hoisted sail and plunged through the weakened center, where there was a fair amount of empty sea between groups of embattled galleys. The queen’s own ship was easy to distinguish because it had a purple sail.
The change in wind direction meant that once Cleopatra’s squadron had rounded Leucas, it could speed south with a following breeze in its sails and make its escape, easily outrunning Octavian’s sailless ships. Antony immediately extricated some vessels from his position in the north. His flagship being too heavily engaged to escape, he transferred to another and made after the queen with a small flotilla.
The ancient sources wrongly suppose that Cleopatra lost her nerve and fled out of cowardice, and that Antony followed her because he was besotted by love. Quite clearly, this was not the case. The stowing of the sails, the order of battle (with the queen’s ships kept in the rear, fresh and clear of the fighting), and the timing of the breakout to catch the afternoon wind indicate that the couple were acting out, with complete success, a carefully laid plan. While Agrippa was aware (thanks to Dellius) that a general breakout was intended, he was not expecting Cleopatra to make a getaway while the rest of Antony’s ships kept him occupied. He had played unknowingly into her hands by sailing north to outflank Antony’s right and so thinning his line.
Antony presumably hoped that other ships of his would also be able to break away, but they were fully engaged trying to fend off Octavian’s larger fleet. After about an hour, the wind strengthened. Some of Antony’s ships began to give up the unequal struggle and surrendered. Others withdrew into the Actium strait.
It is often difficult at the height of a battle for generals or admirals to know what is going on around them. Had Octavian won, or had he lost? He suspected he was the victor, but could not be absolutely sure. The light was failing. There was a swell. It was not always easy to distinguish enemy ships from those of friends. If he received any reports from across a battlefront that was probably not less than four miles long, he could not rely on them. As he was somewhere in the center of his line, he would have witnessed the queen’s departure under full sail, but could have had no idea that Antony had left the scene with her.
What Octavian did see was some sort of retreat by enemy ships. During the wars against Sextus Pompeius he had learned the hard way that admirals were often obliged to spend a sleepless night after a battle at sea. Now that he and Agrippa had probably succeeded in bottling up what remained of Antony’s fleet, they wanted to avoid any risk of it slipping away under cover of darkness or at first light. So, uncomfortable and dangerous though it was, they kept their ships at sea in the Actium roads throughout the hours of darkness.
At daylight Octavian, now back on land, could assess the outcome. He saw now that he had won at least a partial victory. About thirty or forty enemy galleys had been sunk and about five thousand of Antony’s troops killed. The commanders of the remaining one hundred thirty or one hundred forty ships briefly considered their position, realized it was hopeless, and surrendered. However, a sizable army of up to fifty thousand men was holding together under Canidius Crassus, who started leading it toward the Pindos mountains and the relative safety of Macedonia. Unless that force could be neutralized in some way, the battle of Actium would simply be a passing incident in the war, not its decisive encounter. So he marched after Antony’s legions.
As things turned out, he did not need to worry. Until the day after the battle, the soldiers had no idea that their commander had abandoned them. The men longed to see him and were sure that he would soon turn up from somewhere or other. But the days passed with no sound or sight of him, and their confidence collapsed. The time had come for them to do a deal with the victor. In essence, the soldiers demanded to be treated as if they had been on the winning side. After a week of tough negotiations, Octavian agreed to keep the legions in being instead of disbanding them and, most important, he promised to give them the same rewards as the victorious army.
The deal done, Canidius and other senior officers wanted no part of it. One night they left camp secretly and made their sad way to Antony.