Caesar Revenged: Battle of Philippi

On October 3, 42 BC, at the first Battle of Philippi, Mark Antony and Octavian fought an indecisive battle with Caesar's assassins, Brutus and Cassius. From the article:

"Caesar Revenged: Battle of Philippi

Background
Following the assassination of Julius Caesar, two of the principal conspirators, Marcus Junius Brutus and Gaius Cassius Longinus fled Rome and took control of the eastern provinces. There they raised a large army consisting of the eastern legions and levies from local kingdoms allied to Rome. To counter this, the members of the Second Triumvirate in Rome, Octavian, Mark Antony, and Marcus Aemilius Lepidus, raised their own army to defeat the conspirators and avenge Caesar's death. After crushing any remaining opposition in the Senate, the three men commenced planning a campaign to destroy the conspirators' forces. Leaving Lepidus in Rome, Octavian and Antony marched east into Macedonia with around 28 legions seeking the enemy.

Octavian & Antony March
As they moved forward, they dispatched two veteran commanders, Gaius Norbanus Flaccus and Lucius Decidius Saxa, ahead with eight legions to search for the conspirator's army. Moving along the Via Egnatia, the two passed through the town of Philippi and assumed a defensive position in a mountain pass to the east. To the west, Antony moved to support Norbanus and Saxa while Octavian was delayed at Dyrrachium due to ill health.

Advancing west, Brutus and Cassius wished to avoid a general engagement, preferring to operate on the defensive. It was their hope to use Gnaeus Domitius Ahenobarbus' allied fleet to sever the triumvirs' supply lines back to Italy. After using their superior numbers to flank Norbanus and Saxa out of their position and force them to retreat, the conspirators dug in to the west of Philippi, with their line anchored on a marsh to the south and steep hills to the north.

Troops Deploy
Aware that Antony and Octavian were approaching, the conspirators fortified their position with ditches and ramparts straddling the Via Egnatia, and placed Brutus' troops to the north of the road and Cassius' to the south. The Triumvirate's forces, numbering 19 legions, soon arrived and Antony arrayed his men opposite Cassius, while Octavian faced Brutus. Eager to begin the fighting, Antony tried several times to bring about a general battle, but Cassius and Brutus would not advance from behind their defenses. Seeking to break the deadlock, Antony began searching for a way through the marshes in an effort to turn Cassius' right flank. Finding no usable paths, he directed that a causeway be constructed.

First Battle
Quickly understanding the enemy's intentions, Cassius began building a transverse dam and pushed part of his forces south in an effort to cut off Antony's men in the marshes. This effort brought about the First Battle of Philippi on October 3, 42 BC. Attacking Cassius' line near where the fortifications met the marsh, Antony's men swarmed over the wall. Driving through Cassius' men, Antony's troops demolished the ramparts and ditch as well as put the enemy to rout.

Seizing the camp, Antony's men then repelled other units from Cassius' command as they moved north from the marshes. To the north, Brutus' men, seeing the battle in the south, attacked Octavian's forces (Map). Catching them off guard, Brutus' men, directed by Marcus Valerius Messalla Corvinus, drove them from their camp and captured three legionary standards. Forced to retreat, Octavian to hide in a nearby swamp. As they moved through Octavian's camp, Brutus' men paused to plunder the tents allowing the enemy to reform and avoid a rout.

Unable to see Brutus' success, Cassius fell back with his men. Believing that they had both been defeated, he ordered his servant Pindarus to kill him. As the dust settled, both sides withdrew to their lines with their spoils. Robbed of his best strategic mind, Brutus decided to attempt to hold his position with the goal of wearing down the enemy.

Second Battle
Over the next three weeks, Antony began pushing south and east through the marshes forcing Brutus to extend his lines. While Brutus wished to continue delaying battle, his commanders and allies became restless and forced the issue. Surging forward on October 23, Brutus' men met Octavian and Antony's in battle. Fighting at close-quarters, the battle proved very bloody as the Triumvirate's forces succeeded in repelling Brutus' attack. As his men began retreating, Octavian's army captured their camp. Deprived of a place to make a stand, Brutus ultimately committed suicide and his army was routed.

Aftermath & Impact
The casualties for the First Battle of Philippi were approximately 9,000 killed and wounded for Cassius and 18,000 for Octavian. As with all battles from this period, specific numbers are not known. Casualties are not known for the second battle on October 23, though many noted Romans, including Octavian's would-be future father-in-law, Marcus Livius Drusus Claudianus, were killed or committed suicide.

With the death of Cassius and Brutus, the Second Triumvirate essentially ended resistance to their rule and succeeded in avenging the death of Julius Caesar. While Octavian returned to Italy after the fighting ended, Antony elected to remain in the East. While Antony oversaw the eastern provinces and Gaul, Octavian effectively ruled Italy, Sardinia, and Corsica, while Lepidus directed affairs in North Africa. The battle marked the high point of Antony's career as a military leader, as his power would slowly erode until his ultimate defeat by Octavian at the Battle of Actium in 31 BC."