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  • James Houser

August 9, 48 BC - Caesar vs. Pompey at Pharsalus

Updated: Jun 12, 2021

August 9, 48 BC. The last days of the Republic are here. Julius Caesar and Pompey Magnus, the two greatest warlords the city of Rome has ever produced, are about to bring to a climax a generations-old struggle. The legions will fight not the enemies of Rome, but each other, in the epic and decisive battle of Pharsalus. It is the clash of the titans.

This is not the place for an entire history of Rome’s social struggles and the death throes of the old Republic, so I’ll keep it brief. Ever since the defeat of Carthage in 146 BC, the growing power of Rome brought about economic and social transformations that caused widespread political conflict. The rabble-rousing populism of the Gracchus brothers in the 120s BC only brought to light the divide between Rome’s “haves” – the wealthy Senatorial elite – and the “have-nots” – the people at large. Soon Rome had become a city of constant public rioting and scandal, as politics moved from its old orderly routines into a hotbed of urban protest, contested elections, and general upheaval.

The factional infighting of the Roman Republic was further exacerbated by the military reforms of Gaius Marius, who saw the military strength of his city falling apart in the midst of political decay and social turmoil. Marius decoupled the military system from the traditional “citizen farmer” dedicated to serving his country so he could get back to his fields, and instead recruited a mass army from the urban poor and destitute. This move from a citizen militia with a vested interest in the state to a professional soldiery fighting for a wage and a share of the loot DID enhance the ability and lethality of the Roman legion – but at a high price. A Roman general’s fortunes now rested on his ability to deliver stunning military victory, and in turn to secure rewards for his troops. This vicious cycle gave rise to a series of military strongmen who sought to dominate the Roman political system at the point of a sword.

The first to try this was Marius himself. He positioned himself as a man of the people, winning the masses over to his side and helping to initiate Rome’s first true Civil War. After Marius engineered a coup in 88 BC, he was removed from power by his arch-nemesis and former subordinate Lucius Cornelius Sulla. The wars between Marius (for the populists) and Sulla (for the aristocracy) would end with Marius dead and Sulla triumphant six years later. (This war is its own long, tremendous story which I would love to get into but we do NOT have time.) Sulla became the newest military strongman, who promptly set himself up as Dictator in 82 BC and presided over a combination of much-needed reforms and a host of public murders that solidified his rule.

Sulla is one of my favorite historical figures, but we don’t have time (sadly). The upshot of all this is that in the aftermath of Sulla’s Civil War, he stepped down voluntarily (!) from his dictatorship in 79 BC, having hopefully restored the Roman Republic and set it on the road to good old-fashioned greatness. The problem was, of course, that he had just papered over the problems Rome faced. They hadn’t gone away. By the 60s BC, a whole new generation of aspiring military leaders and political revolutionaries had risen up to continue the struggle that Marius and Sulla had only started.

The next major figure to gain a commanding military presence in Rome was Sulla’s former general in the Civil Wars, the handsome, glory-seeking, charismatic and vain Gnaeus Pompeius Magnus, best known to history as “Pompey the Great.” Pompey was a versatile and flexible military leader, never a great politician but easily the most famous and admired soldier in Rome. His conquests in Spain, his assistance in suppressing the Spartacus uprising, his destruction of the pirates that plagued the Mediterranean, and most especially his famous and lucrative campaigns in the East had garnered him enormous prestige and glory. When he returned to Rome in 61 BC, though, the Senate refused to grant him the rewards and land for his troops that he wanted.

Pompey was forced to ally with his longtime political nemesis, Marcus Crassus – another of Sulla’s former generals. Crassus, the richest man in Rome (who I’ve discussed before), wanted favorable tax laws for his many businesses and properties. Together, the political power of these two men would secure both the political elite and the financial interests of Rome in an alliance – but they hated each other, so they needed a third leg to their stool. Someone who could rally the people, mediate between two old rivals, and round out their political problems.

That man was the young up-and-comer, the one, the only, Gaius Julius Caesar. Caesar was immensely popular with the Roman masses, and unlike the other two had been linked with the populist faction of Marius. Caesar wanted political power and a military command. Crassus, Pompey, and Caesar formed a political alliance known as the Triumvirate, by which they could all get what they wanted with the support of the others and dominate Rome. This system worked well, for a time.

So Rome was in the hands of three military strongmen, and by now the old Republic was pretty much dead. Everything else was just digging the grave. Caesar led his army into his famous conquest of Gaul from 58 to 50 BC, while Pompey enjoyed semi-retirement and Crassus went off to get his dumb ass killed trying to invade Persia in 53 BC. (I did a whole post on Crassus’s misadventures). This left only Pompey and Caesar as the two most powerful men in the Roman Republic. Both were intensely ambitious and both knew that to become the first man in Rome, the other had to be taken out. Pompey had an advantage in that he was actually IN Rome, while Caesar was off in the wilds of northern Europe. Caesar had an advantage in that yes, he was off in the wilderness, but he had a veteran army with him.

In 52 BC, Pompey had the Senate give him a great amount of military authority as a direct challenge to his old ally Caesar. This included the command of an army in Spain. Pompey soon began a propaganda campaign against Caesar, whose term as military governor was set to expire in 49 BC. If he wanted to run for that position again, he would have to surrender his army and return to Rome unarmed, where he would be vulnerable to arrest and execution on any charge Pompey could trump up. Caesar declared that he would only disband his army if Pompey disbanded his; Pompey refused, and Caesar knew that he had no other choice.

Caesar only had a single legion on hand when he approached the Rubicon River, which separated his military province from Italy. Pompey commanded a much larger force and was recruiting more units all over Italy and the Mediterranean provinces. Caesar realized his only hope was in boldness – and he had NO shortage of that. In January of 49 BC, Caesar crossed the Rubicon, famously announcing “the die is cast.” The second Roman Civil War – Caesar’s Civil War – was on.

Pompey and the Senate were spooked by Caesar’s quick action, and as soon as they learned he had an army headed for Rome they quickly fled Italy. Caesar followed fast on their heels, only to see them sailing away from Italy off into the sea. Caesar, for now, lacked a fleet to follow. He decided to build up his forces in Italy for the rest of 49 BC, leaving his favorite subordinate Marc Antony in command of Rome. He took his own army, established control of Italy, Corsica, and Sardinia, then sailed to Spain. There he surrounded one of Pompey’s armies and forced it to surrender, and shocked another into giving up as well. On the way back, he knocked off one Pompeian garrison after another. Caesar’s speed, boldness, and violence of force gained him all these victories, from the Crossing of the Rubicon to the subduing of Italy and Spain.

In January 48 BC, Caesar decided that it was time to take the fight to Pompey. Pompey had retreated to the east, where he used his many contacts gained and called in debts accrued during his Eastern conquests. He had put together a much larger force than Caesar, including units from all over the Mediterranean such as Greece, Syria, Israel and Libya. Most of Pompey’s army was inexperienced, though, compared to Caesar’s veterans from his conquest of Gaul. Caesar, though, was used to being outnumbered; he would be outnumbered in every single battle of his career.

Caesar crossed over the sea to land near Dyrrachium (modern Durres in Albania) where he maneuvered his smaller army against the enormous force that Pompey had put together. Poor weather almost prevented half his force from reaching him, but Marc Antony was able to bull through the storms and arrive with reinforcements in time to save Caesar from disaster in March of 48 BC. Pompey had set himself up in the hills around Dyrrachium, and Caesar decided to confront him there.

The Battle of Dyrrachium was more like a long siege, as Caesar tried to build a wooden wall to surround Pompey’s army and Pompey built his own wall in response. Caesar knew he was outnumbered and relied on his soldiers’ experience and engineering acumen to build better fortifications faster, but Pompey had twice the men to dig. The mirroring trenches and walls resembled something like an ancient First World War as the two armies tried to dig their way to victory. Finally, Pompey spotted a gap in Caesar’s trenches, and on July 10 he struck, forcing Caesar into retreat.

The difference between Caesar and Pompey was highlighted by the follow-up to the Battle of Dyrrachium. Pompey failed to pursue Caesar with speed or ruthlessness; instead, he detached a large part of his army to hold his base at Dyrrachium and cautiously trailed his foe into the heart of Greece. He had positioned another army in northern Greece and tried to trap Caesar against it. For most of July, Caesar avoided being surrounded by these two forces. Pompey could have left and retaken Rome at this point – Caesar was cut off from outside help, Pompey had the bigger army, and his fleet had taken control of the sea – but he was unwilling to leave such a dangerous opponent at his back.

The two armies finally ended up squaring off at a wide plain in northern Greece near the town of Pharsalus. They established camps only a few miles apart, facing each other. Every day, Caesar placed his smaller army of 22,000 men closer to Pompey, hoping to encourage him to attack. Pompey, with 54,000, was unwilling to leave his superior defensive position; he knew that Caesar’s food stocks were dwindling, and he only had to wait him out. The Senatorial leaders in Pompey’s camp, though, harangued him into attacking and finishing Caesar off immediately. Caesar’s army – tired, outnumbered, hungry – was about to break camp and retreat on August 9, 48 BC, when they saw that Pompey had finally come out for a fight.

Pompey’s army was much larger than Caesar’s, but the primary difference was in command. Pompey, once Rome’s greatest general, was far past his prime and bedeviled by meddlesome senators second-guessing his every move. Caesar was solely in command, with troops that had followed him through years of campaigns and imbued with utter self-confidence. This difference was reflected in the speeches they gave their men.

Pompey basically said “Soldiers, this fight is being forced on me, so if we lose, it’s their fault. We outnumber them, we’re right, and we’ve got food in our bellies, so we’re obviously going to win.”

Caesar basically said “My friends, you promised me and each other that you’d never run away. The guys in charge of this army are the elites, you’re the people. I love you all. Pompey’s a pussy. They’re a bunch of worthless foreigners. We’re hungry, we’re outnumbered, our backs are to the wall. Victory or death.”

Who would you fight for?

Pompey deployed the vast majority of his cavalry on his southern flank, with the goal of turning Caesar’s flank and driving Caesar’s smaller army into the river to the north. Caesar anticipated this. Hidden behind his own (much smaller) cavalry force, he had placed a reserve unit of his best infantry. Despite Pompey’s greater numbers, Caesar struck first, sending his infantry forward in an impetuous attack. The Battle of Pharsalus was on.

Caesar’s veteran legionnaires launched themselves across the field into Pompey’s front line, and the two Roman armies clashed in a fierce fight beneath the hot August sun of Greece. As expected, Pompey launched his cavalry at Caesar’s flank. Caesar’s cavalry scattered out of the way, as ordered, revealing the hidden infantry unit formed into a wall of spears. The wave of Pompey’s horsemen shattered on this rock, which drove the inexperienced horsemen from the field and sent them retreating into the hills. Caesar’s cavalry and infantry charged, slicing into the unprotected archers and slingers that had been uncovered by the massacre of the cavalry. This left Pompey’s flank open, and the tables had turned as Caesar’s smaller army began to squeeze the larger in a vise.

Pompey at this point panicked and fled, leaving his leaderless troops shaken and collapsing. Caesar’s men drove the Pompeian army all the way back to their camp, which they proceeded to surround and loot. Soon the remainder of Pompey’s army was surrounded on a hilltop, where they surrendered the next morning. Pompey himself hopped a ship and sailed off to Egypt, where he sought refuge with the reigning Pharaoh. Instead, he found death when Ptolemy XII decided to make Caesar a gift of Pompey’s head.

Caesar’s Civil War was not over – he had three more years of fighting left before he subdued the final holdouts from Pompey’s faction. At Pharsalus, though, he had totally changed the course of Roman history. He was now the supreme man in Rome, the successful military dictator to rival all military dictators, basking in the adoration of the public and the love of his soldiers. He had himself appointed dictator for life, which finally drove the remaining Senators over the edge and caused his assassination in 44 BC.

But killing Caesar could not undo what he had unleashed; the genie could not be put back in the bottle. With Caesar’s victory at Pharsalus, the victory of military dictatorship over the old Senate was assured for all time. The era of one-person rule with a virtual rubber-stamp Senate began with Caesar and was set in stone by his adopted son and successor Octavian, who would become the first Roman Emperor as Augustus Caesar. Had Pompey won the Battle of Pharsalus, he may have tried to do the same thing – but being older and less politically able, he might have failed.

Pharsalus was Caesar’s greatest victory in a freaking catalog of great victories that I wish I had the time to tell you all about. Without this triumph, though, Caesar as we know him wouldn’t be a thing. No Caesar salad, no Tsars or Kaisers, no Roman Empire, and no month of July (named after Julius Caesar) or August (named after Augustus.) Imagine having a month of Pompey. Doesn’t roll off the tongue.

When I get a chance I’ll tell you all about Caesar in Egypt and how he got it on with Cleopatra.

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