In 42 BC, the Roman world stood on a knife-edge between two factions: the Optimates and the Populares. Julius Caesar's assassination in 44 BC had ignited a fire that burned for years before it reached Philippi. Brutus and Cassius, known as the Liberators, fled Italy to control eastern provinces from Greece to Syria. They gathered allies and legions to challenge the rising power of Mark Antony and Octavian. The Second Triumvirate formed in Rome with three leaders: Antony, Octavian, and Lepidus. Their goal was clear. They needed to crush the Liberators' forces to secure full control of the Roman world. Avenge Caesar's death became their public justification, but political dominance was the true engine driving them forward. Antony and Octavian moved their best troops into northern Greece while Lepidus stayed behind in Italy. Eight legions under Norbanus and Saxa marched along the Via Egnatia to scout enemy positions. These men took a strong defensive position at a narrow mountain pass near Philippi. Antony followed closely behind his scouts. Octavian lagged due to severe illness that would plague him throughout the campaign. Republican admiral Gnaeus Domitius Ahenobarbus arrived with 130 ships to block supply lines back to Italy. The Liberators spent months plundering Greek cities to build up their war chest. They chose Thrace as their base and fortified high ground on both sides of the Via Egnatia. Their southern flank rested against an impassable marsh while hills blocked their northern side. Brutus positioned his camp to the north and Cassius held the south.
Strategic Movements And Fortifications
Antony ordered his army to cut through the marshes south of the Liberators' position. He threw up a causeway over the water with great effort. Cassius noticed this maneuver and countered by moving part of his army into the marshes. He constructed a transverse wall to cut off Antony's outstretched right wing. This brought about a general battle on the 3rd of October 42 BC. Antony charged directly at Cassius's fortifications between the camp and the marshes. Brutus's soldiers rushed against Octavian's army without waiting for the attack order. Their watchword was Liberty, but they acted on impulse rather than command. Octavian's troops fled and were pursued up to their own camp. Marcus Valerius Messalla Corvinus led Brutus's men who captured the enemy stronghold. Three of Octavian's legions lost their standards, signaling a complete rout. Octavian himself vanished from his tent where his couch had been pierced and cut to pieces. Ancient historians claim he hid in the marsh after receiving a dream warning. Pliny reported that Octavian went into hiding during the chaos. Meanwhile Antony stormed Cassius's fortifications and demolished the palisade. He filled up the ditch and took Cassius's camp easily. Part of Cassius's army had advanced south and was repulsed when trying to return. The battlefield stretched so wide that dust clouds made assessment impossible. Both wings remained ignorant of each other's fate until later.