After the violent death of Julius Caesar in 44 BCE, civil war broke out between on the one hand the assassins, republicans like Brutus and Cassius, and on the other hand the Caesarians, led by Mark Antony and Octavian. Mark Antony, one of the best generals of his age and beloved like a god by his men, overcame the last republicans in 42 at Philippi, and started to reorganize the eastern half of the Roman empire. Meanwhile, Octavian accepted the west.
The relations between the two men had never been friendly, but they tried to make the best of it; Octavian married his sister Octavia Minor to Mark Antony, who for a while lived without his oriental mistress Cleopatra VII Philopator, the queen of Ptolemaic Egypt. However, he returned to her and it was even discovered (in a probably forged document) that Antony had committed treason: he wanted to give her Roman land.
This was the excuse Octavian needed to declare war. He had probably prepared it for some time: in the preceding years, he had annexed Dalmatia, which would offer him a land road from Italy and Gaul to the Balkans, and was almost certainly a preliminary to a war against Antony.
In 32, Cleopatra and Antony started to sail to the northwest, where they wintered in Ephesus, to proceed to Greece and Epirus. Their navy consisted of 230 vessels and 50,000 sailers; their army may have counted as many as 23 legions (paper strength 115,000 men) and auxiliary troops. Antony's plan was to cross to Italy, but his advance was halted when Octavian sailed to the east with about 100 ships and landed in Dalmatia. He could also muster 24 legions, or 120,000 soldiers (paper strength). With this army, he now marched to the south, and established a bridgehead at the Gulf of Ambracia, immediately north of the entrance.
At the same time, Octavian's trusted right-hand man Agrippa sailed to the western Peloponnese with 300 war galleys, and occupied several positions. This manoeuver cut off Antony's line of communication and made it difficult to supply his immense army. Having done this, Agrippa sailed to the north, established another important base at Patras, and finally joined Octavian.
In the meantime, Antony had reached the entrance of the Gulf of Ambracia too, hoping that Octavian would offer battle, which he refused. Antony occupied the southern peninsula, called Actium, "promontory", and proceeded to build a bridge to the northern promontory, where he built a second camp. However, Octavian refused to be lured into battle - and wisely so, because Mark Antony was by far the better commander.
Time was on Octavian's side. The operations of Agrippa had isolated the army of Antony and Cleoptatra, and hunger was beginning to wear out Antony's men. This forced him to fight at sea: he had to break out from the Gulf of Ambracia. This was to Octavian's advantage: his friend Agrippa was an excellent admiral, whereas Mark Antony had never shown himself to be a capable commander at sea.
The decisive battle was fought on 2 September 31, during the afternoon, when the northern winds, which are common on the Mediterranean Sea, would favor Antony's break-out plan. Octavian and Agrippa strengthened the wings of their navy, because they wanted to prevent Antony from outflanking them. Antony, however, wanted to break away, and ordered the main attack through the weakened center. And indeed, when the battle began, Antony's center defeated the center of Agrippa and Octavian, which was commanded by Lucius Arruntius.
Cleopatra's ships - which contained the treasury - quickly passed through the gap, followed by Antony's ships, which had been stationed on the right wing. Having reached the open sea, Antony and Cleopatra ordered their ships to raise the sails, and go to the south, benefiting from the increasing northern wind.
After the flight of their commander, the remainder of Antony's navy was seriously demoralized, and was defeated by Agrippa, Octavian, and Marcus Lurius. The Greek historian Cassius Dio offers a terrible description of the way in which the ships from Italy, which were lighter and easier to turn, attacked the large galleys from the east; with catapults, torches were shot to the ships of Antony, and in the end, his fleet burned to destruction.note[Dio, Roman History 50.32-35.]
Antony had won a tactical victory: he had broken away from the Gulf of Ambracia - but at the same time, he had suffered a strategic defeat, because he had lost his army, lost his reputation as an honest commander who would never abandon his men, and lost any chance to win the war. Antony's legionaries immediately surrendered to Octavian.
During the winter, Antony's allies started to switch sides (e.g., Herod of Judaea), and in 30, Octavian pursued his enemies to Egypt. When he laid siege to Alexandria, Mark Antony and Cleopatra committed suicide. Now, Octavian could start his one-man rule, calling himself Augustus. He was to be in charge of the empire for more than forty years, long enough to make people accustomed to it and to forget the violence of his coup.
The battle of Actium became an important part of the imperial propaganda. The poet Virgil devoted some of his finest lines to a description of the battle.note[Virgil, Aeneid 8.676-709.] Monuments to commemorate his victory were erected in several cities (e.g., Corinth, Miletus, Palestrina), but the largest one was founded on the site of his camp on the northern peninsula: a new city called Nicopolis, "victory town", a name inspired by a city founded in the Punjab by Alexander the Great.
The relief from Palestrina shown on the last photo also commemorates the end of the civil war, but at the same time covers up what really happened. The crocodile is the symbol of Egypt, as if the war was a fight against a foreign enemy. But it was, of course, a civil war: Roman was fighting against Roman, and Cleopatra was nothing but a faithful ally of one of the Romans.