Why Did Caesar Win the Battle of Pharsalus?

Why Did Caesar Win the Battle of Pharsalus?

9 August 48 BC – Battle of Pharsalus

Roman Empire

“Because of them Rome was being compelled to fight both in her own defense and against herself, so that even if victorious she would be vanquished.” (Cassius Dio)

The middle of the First Century BC was a time of civil war in the Mediterranean world of the Roman Republic. The great general Pompey Magnus had campaigned deep in the east to the shores of the Caspian Sea to double the revenue and size of the republic as he brought the Levant under Roman rule. He was often shunned by his contemporaries in the Senate for his Gallic lineage but, having risen to fame with his audacity under the dictatorship of Sulla and assuming command of his father’s legions, he had campaigned in Hispania before his eastern expedition.

Pompey had embedded himself in the camp of the conservatives as he fought against the populist Marius and crushed the last holdout of his movement in Hispania long after his death. His eastern campaign would see much of Asia Minor (modern Turkey) and the Levant come under Roman dominion as he assumed control of the plethora of smaller states, dissolving the Seleucid Empire to leave Rome’s eastern frontier with the mighty Parthian Empire and hoovering up the wealth of the east.

Control of the state had been contested by Pompey and his great contemporary rival Marcus Crassus, a man who had grown obscenely wealthy under the proscriptions of Sulla to see his fortune match that of Rome’s annual income. The two agreed to a power sharing deal with a third junior party to balance this fragile triumvirate – Gaius Julius Caesar. This agreement held and froze many of the Senators out of having any say in the republic’s operation, and was cemented by the marriage of Caesar’s daughter to Pompey.

Lucanus: De bello civili (Pharsalia) Lucan (born A.D. 39 in Cordoba, Spain), brother of the famous Stoic philosopher Seneca, was well-known as a writer and moved in the circles close to the Emperor Nero. In A.D. 62 or 63 he published the first three books of his epic poem composed in hexameters, De bello civili (Greek: Pharsalia), in which he describes the civil war between Caesar and Pompey. Lucan’s work was much read in the Middle Ages and in the wake of the Italian humanism of the Trecento.

The death of Crassus at the disastrous Battle of Carrhae in 53 BC, coupled with the death of Caesar’s daughter in childbirth, left the two remaining triumvirs in a state of opposition. While Pompey’s star faded despite his dominion in Rome, Caesar became the new man with his epic conquest of Gaul and campaigns into Britannia and Germania. The conservative faction around Pompey made increasingly absurd demands for Caesar to return to face charges of treason and be stripped of his imperium that protected him from prosecution.

To return to Rome would see Caesar powerless against the scheming of his rivals, with Pompey already having his legions camped around the Eternal City to quell the rising tide of political violence. The stalemate that developed was shattered when the bold Caesar crossed the Rubicon, the river which marks the boundary of Rome and thus no mobilized armies can be brought with, on 10 January 49 BC with a single legion. Panicked, Pompey and the Senate fled east across the Adriatic to Illyria, leaving behind the treasury in the rush to evacuate the city as more and more men swarmed to Caesar’s banners on his march south.

Caesar now faced Pomepy’s veterans to his west in Hispania and to his east as the great general himself gathered a huge army of all the veteran legions in Greece plus the promises of huge payments and levies from all his clients in the east.

First was a lightning march and swift campaign to defeat the leaderless rebel legions in Hispania at Ilerda, before a year spent consolidating his position in Rome. Caesar crossed the Strait of Otranto in Winter 48 BC to surprise his opponents by landing in Greece with seven legions. Speed was Caesar’s hallmark, and while it served him well on campaigns like Ilerda, it could also be his undoing. While he had reached Illyria and dodged Pompey’s blockade, it was with just half an army and little hope of receiving reinforcements. He realized that his situation was dire as the juggernaut of Pompey’s army loomed large, though offers of negotiation were rebuffed.

After several attempts, Caesar’s adjutant Mark Antony penetrated the blockade and landed with four more legions in Illyria. Caesar and Pompey now raced to reach Antony, and though Pompey reached him first, he moved his army to the town of Dyrrachium to avoid being trapped between Antony and Caesar, who was close behind. Pompey had found a strong defensible position, guarded by the sea and hills, and thus Caesar set about to besiege his army as he had the great Gallic leader Vercingetorix at Alesia.

There were constant skirmishes between the two sides, to little avail, and although Caesar held the surrounding lands, Pompey’s army had already foraged them clean and were now resupplied by sea. Pompey’s men were Roman legionaries though rather than Gallic tribesmen, and when Caesar’s line stretched too thin and Pompey’s managed to land some troops south of a weak point in his fortification, his veterans were broken and given ground.

Pompey moved his cavalry to outflank Caesar, who attempted to manage a retreat, though it soon became a disorganized rout. The counterattack had failed completely, and Caesar himself was unable to prevent the flight of his legionaries. Pompey believed the retreat was a feigned one by Caesar, and refused to give chase to destroy his army. Caesar later remarked: “Today the victory had been the enemy’s, had there been any one among them to gain it.” The Battle of Dyrrhachium on 10 July was a rare defeat for Caesar’s largely impeccable record.

Caesar’s army managed to retreat south into Greece and avoid being caught by Pompey’s cavalry, which outnumbered his own around four to one. He entered Thessaly and regrouped with the forces under his adjutant Calvinus, capturing the town of Gomphi while reinforcing the towns he held. Pompey joined his force with the legions under his lieutenant Nasica, so he now had a force of almost ten legions, 7,000 cavalry, and light auxiliaries. Caesar’s army was around half the size of Pompey’s and rather than being the aggressor he now found himself retreating east, though he would soon be at the Aegean.

Pompey remained loath to attack Caesar, preferring to mirror him and starve out his army, though he was coming under increasing pressure from the senators with him to restore Roman honor and crush Caesar in a decisive battle. With his options running out, Caesar chose to make his stand at the town of Pharsalus on 9 August.

Formation of battle lines for the Battle of Pharsalus, 48 BC Created based on Plutarch: Caesar, c. 44; in Plutarch, Roman Lives, trans. Robin Waterfield, ISBN 9780192825025

Pompey lined his forces with his right flank to the river, with his legionaries in their usual three blocks, though ten-men deep, to absorb Caesar’s charge and prevent the front ranks from breaking. Caesar matched Pompey’s line, though his ranks were just six-men deep given his inferior numbers. Their cavalry faced one another at the far flank (Pompey’s left, Caesar’s right), though Caesar hid a fourth block of infantry behind his small cavalry force.

Pompey provoked further disdain from the senators with him when he refused to march forward to meet Caesar, though he believed this would fatigue his enemy while making his own men better able to defend against thrown pila (javelin). However, Caesar’s men paused just short of throwing distance to allow a chance to recover, before advancing into Pompey’s troops. As the infantry clashed, Pompey’s superior cavalry moved to attack Caesar expecting to push them back and then roll up the flank of his infantry. As expected, they pushed back Caesar’s cavalry and prepared to close the trap.

Jean Fouquet – The Flight of Pompey after the Battle of Pharsalus – WGA08035

This was when Caesar unveiled his hidden fourth line, which jumped up from high grass and thrust their pila at Pompey’s cavalry, instead of throwing them. This caused chaos and hundreds of casualties, and with a regrouped cavalry charge from Caesar’s men, Pompey’s horsemen either fled the field or plowed back into his left infantry wing. Caesar now ordered the advance of his battle-hardened right wing, which bulldozed through the chaos of the raw recruits on Pompey’s left and routed them.

With the trap reversed, the battle was won. Pompey lost the will to fight as he saw his legions and cavalry routing, retreating to his camp and abandoning his army. He ordered a garrison to defend the camp, then gathered his family and his gold, discarded his general’s cape and retreated. Caesar urged his men against the confused and leaderless army, routing the rest of them and capturing the camp. Pharsalus was Caesar’s greatest victory – he had routed an army of Roman legionaries twice his size, under one of Rome’s greatest generals, killing 6,000, accepting the surrender of over 30,000, while losing only 200 of his own men, and 30 centurions. He praised the courage and discipline of his men for winning him the battle.

Pompey reached Larisa and boarded a grain ship with 30 cavalrymen. Caesar was hot in pursuit to prevent Pompey from raising a fresh army, and the latter thus fled to Mitylene on Lesbos. Gathering provisions in Antalya, he heard Cato the Younger was making plans for Africa, and while he considered an alliance with Parthia, he was advised the royal palace would not be safe for his family. He landed at Cilicia, then Cyprus, where his plans to raise a fresh army in Syria were thwarted when he learnt the governor of Antioch had declared for Caesar, as had Rhodes.

His options were becoming increasingly limited, his patronage counting for increasingly less. People in the Ancient World were very superstitious, and would often believe in signs and omens, among the most prominent being the results of battles. A result such as Pharsalus, where Pompey was defeated by a much smaller army, was a damning indictment that the gods had abandoned the once-great general.

Taking what money and soldiers he could gather for his odyssey, Pompey heard that the Egyptian King Ptolemy XIII was at war with his sister-wife Cleopatra VII, and thus sent to the pharaoh for aid. Some Egyptians advised driving Pompey away, others in welcoming him and forging an alliance. Theodotus of Chios said neither was safe, for either would make a powerful Roman enemy. Many of Pompey’s veterans had settled in Egypt following his eastern campaigns, and there were fears he could raise them as a force to turn Egypt into a Roman vassal.

On 28 September, Pompey’s fleet was met with a small fishing boat from the Egyptians. His men viewed this lack of pomp with suspicion and urged him to leave, though the Egyptians said the shallow rocky seabed prevented their ships approaching, and that their army was on shore to welcome him. Pompey boarded the boat, despite his wife Cornelia wailing that he would be killed. The lack of friendliness caused Pompey to remark to one of those present, Septimius, that they were former comrades, though he merely nodded.

He then proceeded to unsheathe his sword and plunge it into Pompey’s belly, the two others aboard sinking their daggers into him. The ship he had come on fled, the favorable winds preventing an Egyptian pursuit. Pompey’s head was hacked off, and his body discarded into the sea. He was a day short of his 58th birthday. Pompey the Great, the head of the Optimate faction, was dead. Ptolemy had the head preserved, eagerly awaiting the arrival of a grateful Julius Caesar to whom he could present this gift. Yet Caesar would not welcome the gift, and instead by incensed by the audacity of a foreigner in murdering a consular Roman and denying him the chance to show his customary clemency to an enemy.

He would interfere in Egyptian affairs to remove Ptolemy from the throne, ensuring Cleopatra would become sole pharaoh and the last of that dynasty. Caesar’s star would rise higher still with none able to stop him on the battlefield as he crushed Egyptian rebels at the Nile, ended Pontic independence at Zela, defeated Cato and his followers at Thapsus, then vanquished the sons of Pompey and his remaining veterans in Hispania.

It would instead by the Senate floor where he would be defeated, murdered by a growing conspiracy of opposition against him to ensure that each of the three triumvirs met a bloody end. His death would not restore the republic though, for out of the shadows would step his adjutant Antony to contest inheriting that great legacy with the unknown Octavian, who was surprisingly adopted posthumously in Caesar’s will and would go on to thwart all of his opponents to forge Rome into an empire.

Why Did Caesar Win the Battle of Pharsalus?

Written by Jack Tappin

Written by Jack Tappin

Roman Empire