Battle of Philippi - Prelude

Prelude

After the murder of Caesar, Brutus and Cassius (the two main conspirators, also known as the Liberatores) had left Italy and taken control of all Eastern provinces (from Greece to Syria) and of the allied Eastern kingdoms. In Rome the three main Caesarian leaders (Antony, Octavian and Lepidus), who controlled almost all the Roman army in the west, had crushed the opposition of the senate and established the second triumvirate. One of their first tasks was to destroy the Liberators’ forces, not only to get full control of the Roman world, but also to avenge Caesar’s death.

The triumvirs decided to leave Lepidus in Italy, while the two main partners of the triumvirate (Antony and Octavian) moved to Northern Greece with their best troops (a total of 28 legions). They were able to ferry their army across the Adriatic and sent out a scouting force of eight legions (commanded by Norbanus and Saxa) along the via Egnatia, with the aim of searching for the Liberators' army. Norbanus and Saxa passed the town of Philippi in eastern Macedonia and took a strong defensive position at a narrow mountain pass. Antony was following, while Octavian was delayed at Dyrrachium because of his ill-health (which would accompany him throughout the Philippi campaign). Although the triumvirs had been able to cross the sea with their main force, further communications with Italy were made difficult by the arrival of the Liberatore admiral Ahenobarbus, with a large fleet of 130 ships.

The Liberators did not wish to engage in a decisive battle, but rather to attain a good defensive position and then use their naval superiority to block the triumvirs’ communications with their supply base in Italy. They had spent the previous months plundering Greek cities to swell their war-chest and had gathered in Thrace with the Roman legions from the Eastern provinces and levies from allies. With their superior forces they were able to outflank Norbanus and Saxa, who had to abandon their defensive position and retreat west of Philippi. Thus, Brutus and Cassius could seize a strong defensive position holding the high ground along both sides of the via Egnatia, about 3.5 km west of the city of Philippi. The south position was anchored to a supposedly impassable marsh, while on the north to impervious hills. They had plenty of time to fortify their position with a rampart and a ditch. Brutus put his camp on the north while Cassius on the south of the via Egnatia. Antony arrived shortly and positioned his army on the south of the via Egnatia, while Octavian put his legions north of the road.