At Philippi in Macedonia in October 42 BC, Mark Antony and the young Octavian defeated Marcus Brutus and Gaius Cassius, the leaders of the plot that had murdered Julius Caesar two years earlier. It was fought in two battles: in the first Cassius killed himself after a partial defeat, and in the second Brutus was beaten and did the same. Their deaths ended the cause of the Roman Republic and cleared the way for the rule of the Caesars.
Two years after the daggers of the Ides of March, the men who killed Julius Caesar and the men who avenged him brought their armies to the plain of Philippi in northern Greece. What was decided there, in two great battles fought three weeks apart, was nothing less than whether Rome would remain a republic or pass forever to one-man rule.
After the Ides of March
When Julius Caesar was murdered in 44 BC, his heir Octavian and his lieutenant Mark Antony set aside their own rivalry, joined Lepidus in the Second Triumvirate, and hunted down Caesar's enemies in a wave of proscriptions that claimed even Cicero1. The chief assassins, Marcus Brutus and Gaius Cassius, had meanwhile gathered a huge army and the wealth of the eastern provinces. In 42 BC the triumvirs crossed the Adriatic to destroy them.
The armies at Philippi
The forces that met near Philippi were vast, perhaps nineteen legions on the triumviral side and seventeen for the Liberators1, with tens of thousands more auxiliaries and cavalry, among the largest Roman armies ever to face each other. Brutus and Cassius took strong high ground astride the Via Egnatia and fortified two camps, planning to let hunger and time do their work rather than risk everything on a battle.
The first battle
On about 3 October Antony forced the issue.1 He stormed Cassius's lines and overran his camp, while on the other wing1 Brutus's troops broke through and took Octavian's camp, Octavian himself, who was sick, being absent from it2. In the dust and confusion Cassius, cut off and wrongly believing the whole army was lost, had one of his own men kill him2. It was in truth a drawn day, but the Liberators had lost their ablest soldier.
The second battle
For three weeks Brutus held his position, waiting for hunger to drive off the triumvirs, whose own supplies were running short, while his men grew restless. Around 23 October, pressed by his own officers3, he came down to fight again. This time Antony and Octavian broke his line and his army disintegrated. Brutus escaped into the hills with a few companions and, rather than be taken, fell on his own sword2.
The end of the Republic
Philippi was the largest and one of the most decisive battles1 of the Roman civil wars. With Brutus and Cassius dead, the cause of the Republic was finished4; no one would again raise an army to restore it. The Roman world was carved up among the victors, and the only question left was which of them would rule it, a rivalry between Antony and Octavian that would run on until Actium in 31 BC and the rise of Octavian as the emperor Augustus.