FIRST BATTLE OF PHILIPPI, 3RD OCT, 42 BC

FIRST BATTLE OF PHILIPPI, 3RD OCT, 42 BC

The battle would involve the largest number of troops in Roman warfare up to that point. 19 legions of 110,000 men on the Triumvirate side faced 17 Republican legions of 90,000 men.

 The Triumvirs had a force of 13,000 cavalry and one extra legion stationed at nearby Amphipolis whilst the Republicans had two legions guarding the fleet and a cavalry force of 17,000 on the plain. 

The Republican army was then, not only smaller but it also consisted of a much more varied mix of troops taken from across the empire.

In the field Cassius took advantage of two mounds located above the plain of Philippi to make two fortified camps for his nine legions. Brutus and his eight legions camped at the foot of the mountains and a palisaded corridor was built to connect the two Republican armies.

 Both camps received additional protection from the Gangites River. The two camps were a significant 2.7 km apart though, which meant the two armies could not easily offer mutual support. 

Antony, therefore, concentrated on Cassius' camp and, with typical bravery, established his army of ten legions in a well-fortified camp a mere 1.5 km from the enemy. Ten days later, Octavian's army of nine legions arrived.

Several early attempts by Antony and Octavian to draw the enemy down to the plain failed completely. As a consequence, Antony, while still making a show of troop manoeuvres on the plain, attempted to cross the reed marshes undetected by building a causeway and, when behind the Republican camps, try to cut their supply lines. 

Cassius soon got wind of the strategy and responded by trying to cut off Antony's advance forces by himself building a transverse wall from his camp to the marshes. Seeing his plan had been discovered, on October 3rd, Antony led a direct assault on Cassius' wall overwhelming the stunned left flank of the enemy and destroying their fortifications. 

Then, while the bulk of Cassius' army was engaged on the plain, Antony went straight for Cassius's largely undefended camp. As things swung against Cassius' legions on the plain and when they saw their camp routed a chaotic retreat followed.

Meanwhile Brutus was doing well against Octavian's legions who, caught by a surprise charge from Brutus' over-eager advance troops which had necessitated the whole Republican army mobilising in support, were routed in a chaotic battle during which Octavian's camp was captured. Fortunately, Octavian - ill again and missing the battle - had taken refuge in the marshes and avoided certain capture.

 Brutus, on discovering the loss of Cassius' camp, sent reinforcements but Cassius, holding out with a small force on the acropolis of Philippi, interpreted them as more of Antony's forces and so committed suicide - as it happened on his birthday - rather than be captured. 

While all this was happening Antony and Octavian's reserve troops, arriving by sea, were destroyed crossing the Adriatic by the Republican fleet. Thus, the first battle of Philippi ended, more or less, in a 1:1 draw, with 9,000 losses on the Republican side and more than double that figure from Octavian's army.