Editing Mark Antony (section)

===War against the Liberators===
{{main|Liberators' civil war|Battle of Philippi}}

Due to the infighting within the triumvirate during 43 BC, Brutus and Cassius had assumed control of much of Rome's eastern territories, and amassed a large army. Before the triumvirate could cross the [[Adriatic]] into Greece, the triumvirate had to address the threat posed by Sextus Pompey and his fleet. From his base in Sicily, Sextus raided the Italian coast and blockaded the triumvirs. Octavian's friend and admiral [[Quintus Salvidienus Rufus]] thwarted an attack by Sextus against the southern Italian mainland at [[Rhegium]], but Salvidienus was then defeated in the resulting naval battle because of the inexperience of his crews. Only when Antony arrived with his fleet was the blockade broken. Though the blockade was defeated, control of Sicily remained in Sextus' hand, but the defeat of the ''liberatores'' was the triumvirate's first priority.

[[File:Phil2.png|300px|thumb|right|First Battle of Philippi – 3 October 42 BC]]
[[File:Phil3.png|300px|thumb|right|Second Battle of Philippi – 23 October 42 BC]]
In the summer of 42 BC, Octavian and Antony sailed for Macedonia to face the ''liberatores'' with nineteen legions, the vast majority of their army<ref name="ReferenceA">Appian, ''The Civil Wars'', Book 14, CVIII</ref> (approximately 100,000 regular infantry plus supporting cavalry and irregular auxiliary units), leaving Rome under the administration of Lepidus. Likewise, the army of the ''liberatores'' also commanded an army of nineteen legions; their legions, however, were not at full strength while the legions of Antony and Octavian were.<ref name="ReferenceA" /> While the triumvirs commanded a larger number of infantry, the Liberators commanded a larger cavalry contingent.<ref>Hinard, 2000, p. 850</ref> The ''liberatores'', who controlled Macedonia, 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 Rome's client kingdoms.

Brutus and Cassius held a position on the high ground along both sides of the ''[[via Egnatia]]'' west of the city of [[Philippi]]. The south position was anchored to a supposedly impassable marsh, while the north was bordered by 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 occupied 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. Antony offered battle several times, but the ''liberatores'' were not lured to leave their defensive stand. Thus, Antony tried to secretly outflank the Brutus and Cassius' position through the marshes in the south. This provoked a pitched battle on 3 October 42&nbsp;BC. Antony commanded the triumvirate's army due to Octavian's sickness on the day, with Antony directly controlling the right flank opposite Cassius. Because of his health, Octavian remained in camp while his lieutenants assumed a position on the left flank opposite Brutus. In the resulting first battle of Philippi, Antony defeated Cassius and captured his camp while Brutus overran Octavian's troops and penetrated into the Triumvirs' camp but was unable to capture the sick Octavian. The battle was a tactical draw, but due to poor communications Cassius believed the battle was a complete defeat and committed suicide to prevent being captured.

Brutus assumed sole command of the army and preferred a [[war of attrition]] over open conflict. His officers, however, were dissatisfied with these defensive tactics and his Caesarian veterans threatened to defect, forcing Brutus to give battle at the second battle of Philippi on 23 October. While the battle was initially evenly matched, Antony's leadership routed Brutus' forces. Brutus committed suicide the day after the defeat and the remainder of his army swore allegiance to the Triumvirate. Over fifty thousand Romans died in the two battles. While Antony treated the losers mildly, Octavian dealt cruelly with his prisoners and even beheaded Brutus' corpse.<ref>Jallet-Huant, 2009, pp. 144–153</ref><ref>Hindard, 2000, pp. 850–851</ref><ref>Cosme, 2009, pp. 56–57</ref>

The battles of Philippi ended the civil war in favor of the triumvirs. With the defeat of Brutus and Cassius, only Sextus Pompey and his fleet remained to challenge the triumvirate's control of the Roman world.