Battle of Pharsalus
Part of Caesar's civil war
Date August 9, 48 BC Location Pharsalus (Greece) Result Decisive Populares victory
Combatants
Populares	Optimates
Commanders
Gaius Julius Caesar	Gnaeus Pompeius Magnus
Strength
Approximately 22,000 legionaries, 5,000-10,000 Auxiliaries and Allies, and Allied Cavalry of 1800	Approximately 60,000 legionaries, 4,200 Auxiliaries and Allies, and Allied Cavalry of 5,000-8,000
Casualties
1,200	6,000

Caesar's Civil War
Massilia (land) – Ilerda – Massilia (naval) – Utica – Bagradas River – Dyrrhachium – Pharsalus – Ruspina - Thapsus – Munda

The Battle of Pharsalus was fought at Pharsalus (Greece) on August 9 48 BC, between the Populares faction of the Roman Republic, led by Gaius Julius Caesar, and the Optimates faction, led by Gnaeus Pompeius Magnus. The victory of Caesar weakened the Senatorial forces and solidified his control over the Republic.

Prelude

Pompey and the Roman Senate fled Italy for Greece in 49 BC to prepare an army. Caesar, for lack of a fleet, solidified his control over the western Mediterranean — Spain and North Africa, specifically, before assembling ships to follow Pompey. Caesar therefore marched overland through southern France, blockading what is now Marseille, and managing to assemble a small fleet. After crushing Pompey's forces in Spain, Caesar focused once again on Pompey and his troops in Greece. Pompey had a large fleet, as well as much support from all Roman provinces and client states east of Italy. Caesar, however, managed to cross the Adriatic in the winter, with Mark Antony following a little later because Caesar lacked sufficient ships. Although Pompey had a larger army, he recognized that Caesar's troops were more experienced, and could prove victorious in a pitched battle. Instead, Pompey waited Caesar's troops out, attempting to starve them by cutting off Caesar's supply lines. Caesar made a near disastrous attack on Pompey's camp at Dyrrhachium and was forced to pull away.

Pompey did not immediately follow up on his success. An indecisive winter (49–48 BC) of blockade and siege followed. Pompey eventually pushed Caesar into Thessaly and urged on by his senatorial allies, he confronted Caesar near Pharsalus. Caesar began the battle with a smaller, but veteran, force. Pompey's troops were more numerous, but far less experienced. Moreover, Pompey's senatorial allies disagreed with Pompey over whether to fight at Pharsalus, and pushed Pompey, who wanted to starve Caesar's soldiers, into a quick decision.

Caesar had the following legions with him:

• Legions of veterans from the Gallic Wars – Caesar's favourite legion, X Equestris, and those later known with the names of VIII Augusta, VIIII Hispana, and XII Fulminata
• Legions levied for the civil war – legions later known as I Germanica, III Gallica, and IIII Macedonica

However, all of these legions were 'short', and did not have the requisite numbers of troops. Some only had about a thousand men at the time of Pharsalus, due partly to losses at Dyrrhachium and partly to Caesar's wish to rapidly advance with a picked body as opposed to a ponderous movement with a large army.

Battle

Deployment

Both commanders realized that if one army was able to flank the other, they would probably win. As such, both commanders put a substantial amount of effort into ensuring that the other would be unable to 'sneak around to the back'. The battle was held with the River Enipeus to Caesar's left, ensuring that neither side would be able to move around the other army on Caesar's left. The most important part of the battle was to happen on Caesar's right. Pompey hoped to win by using his superior cavalry to mount a two-front attack on Caesar's forces. As such, he placed a large contingent of cavalry on Caesar's right, with light forces consisting of slingers (funditores) and archers (sagittarii). Caesar placed his cavalry on his right, with the fourth battle line in reserve behind the main infantry body and at right angle to it.

Conflict

When the two generals had finished deploying their troops, the infantry began to close. Pompey ordered his soldiers not to charge (against the standards of the day) having a plan of tiring them out. This tactic backfired as Caesar's veteran centurions, foreseeing Pompey's trap, stopped halfway on their charge, and allowed their lines to rest, while Pompey's multi-lingual forces were unable to receive orders easily, leaving Pompey's troops confused, creating a stalemate in the center.

By the river, the light infantry skirmished, before the heavy infantry closed. Titus Labienus led a cavalry charge, and succeeded in pushing back Caesar's cavalry and light infantry. However, when confronted by Caesar's fourth line of heavy infantry, Labienus' charge was pushed back, and the light infantry and cavalry of Pompey's right were pushed into the foothills of Mount Dogandzis. Caesar's fourth battle line wheeled into Pompey's rear at the same moment when Caesar pushed a fresh line of troops into battle. Now facing Caesar's fresh third line at the center of the battle and the attack from behind from Caesar's fourth line, Pompey saw that his defeat was at hand. Caesar told his legionaries to thrust their pilum (plural pila) into the enemy cavalrymen's faces instead of throwing them. Pompey fled the battle while his troops were defeated under pressure. Caesar ransacked Pompey's camp, and took control of the remainder of Pompey's army.

Aftermath

Pompey fled from Pharsalus to Egypt, where he was assassinated on the order of Pharaoh Ptolemy XIII. The Battle of Pharsalus ended the wars of the First Triumvirate, and left Caesar 'supreme commander' of the Roman World. Caesar spent the next few years 'mopping up' remnants of the senatorial faction. After finally completing this task, he was assassinated in a conspiracy arranged by Marcus Junius Brutus and Gaius Cassius Longinus.

Note

The date of the battle is given as 9 August. This is according to the republican calendar. The date according to the Julian calendar, was either 29 June 48 (according to Le Verrier's chronological reconstruction) or 7 June 48 (according to Drumann/Groebe). Pompey was assassinated on September 3rd. The point is not entirely academic; had the battle taken place in the true month of August, when the harvest was becoming ripe, Pompey's strategy of starving Caesar would have been senseless.

Named after battle

The battle gives its name to

• Pharsalia, a poem by Lucan
• Pharsalia, New York, U.S.
• Pharsalia Technologies, Inc.

Further reading

• William E. Gwatkin, Jr., Some Reflections on the Battle of Pharsalus, Transactions and Proceedings of the American Philological Association, Vol. 87. (1956), pp. 109-124.
• Caesar's account of the battle