The Battle of Dyrrachium: How Caesar almost lost the Civil War against Pompey

In 49 BCE, Caesar had crossed the Rubicon River: an act that officially triggered a war with the Roman Senate and, as a result, a civil conflict with the Senate’s leading general, Pompey the Great.

As Caesar’s forces were advancing swiftly south through Italy, Pompey and his supporters fled to the relative security of Greece, where they aimed to regroup and challenge Caesar with fresh troops.

By early 48 BCE, both leaders understood that a decisive confrontation was required to determine the victor.

At this point, Dyrrachium, a strategic coastal city in modern-day Albania (modern Durrës), became a focal point of military maneuvering due to its location and supply routes.

This city offered Pompey a secure base from which to launch a counter-offensive against Caesar's encroaching forces. 

Leading up to the Battle of Dyrrachium, Caesar’s primary goal was to secure a decisive victory over Pompey’s forces to consolidate his power in the Roman Republic.

During his rapid advance across Italy and subsequent campaigns in Spain, Caesar aimed to dismantle Pompey’s influence piece by piece.

In early 48 BCE, after consolidating his power in Italy, Caesar knew he needed to confront Pompey directly in Greece to prevent his rival from gathering more strength.  

To reach Dyrrachium, Caesar undertook a carefully planned and audacious campaign to transport his army across the Adriatic Sea.

Due to limited naval resources, he decided to split his forces for the crossing. Caesar led the first contingent, consisting of about 15,000 men and a smaller number of cavalry, while his trusted lieutenant, Mark Antony, was tasked with bringing the rest of the army.

The plan was risky because it required navigating waters controlled by Pompey's superior fleet, which posed a constant threat to their transport ships.

On January 4, 48 BCE, Caesar managed to embark his initial force from Brundisium, a vital port in southern Italy.

He chose to cross during winter, calculating that the rough seas would deter Pompey’s fleet from patrolling aggressively.

This was a calculated risk that hoped to use the weather to his advantage.

However, the decision proved to be effective, allowing his ships to slip past Pompey’s naval blockade.

Within a few days, Caesar’s forces landed near Palaeste in Epirus, on the opposite coast.

There, they quickly established a beachhead which ensured that his initial landing force would be ready to defend itself against any immediate threats. 

After securing his initial position, he sent his ships back to Italy to bring the remainder of his forces under Antony.

Meanwhile, Pompey, stationed in Dyrrachium with a larger force, quickly became aware of Caesar’s arrival.

However, poor communication and the unexpected timing of Caesar’s crossing caused confusion among Pompey’s ranks.

Although Antony faced difficulties, including bad weather and the threat of Pompey’s fleet, he successfully led the second wave across the Adriatic.

Upon their arrival, the reunited forces moved quickly to link up with Caesar. 

To achieve this, he sought to capture Dyrrachium, a strategically important coastal city that could serve as a supply base and staging ground for further operations.

Furthermore, Caesar believed that taking Dyrrachium would force Pompey into a direct confrontation, where his own recent battlefield experiences could potentially outmatch his rival's cautious strategies.

For Julius Caesar, seizing Dyrrachium was crucial to cut off Pompey's access to resources and reinforcements.

His military experience had taught him the value of speed and surprise, and he moved quickly to besiege the city.

Meanwhile, Pompey, aware of Dyrrachium's importance, fortified his position and prepared to defend against Caesar’s legions.

At the heart of their struggle lay the desire to control the city’s vital harbor and its supply lines.

By establishing a stronghold there, Pompey hoped to isolate Caesar from Italy and force him into a precarious situation.  

Caesar’s military strengths at this time were formidable but came with notable weaknesses.

His legions, numbering around 15,000 to 20,000 men, were battle-hardened and loyal, having followed him through the Gallic Wars and the swift march on Rome.

These experienced soldiers had proven their effectiveness in both offensive and defensive operations, thanks to their exceptional discipline and versatility.

However, Caesar’s forces also faced significant challenges. They were outnumbered by Pompey’s larger army.

Additionally, Caesar’s troops were stretched thin, since they were maintaining control over several territories while also launching an offensive against a well-entrenched enemy.

Also, securing provisions became increasingly difficult as they moved deeper into enemy territory. 

After years of successful campaigns, the troops had an unwavering confidence in Caesar's leadership.

As a result, their morale remained relatively high, encouraged by recent victories and the promise of further spoils and glory.

Knowing he could not afford a prolonged siege without risking severe attrition and loss of morale, Caesar aimed to provoke Pompey into a mistake or draw him into a vulnerable position. 

To sustain his troops, Caesar called for more foraging expeditions into the surrounding countryside.

This was a risky strategy because it exposed his men to attacks from Pompey’s cavalry.

Simply put, Caesar’s leadership relied heavily on the loyalty and morale of his legions, many of whom had followed him through years of campaigning.

Also, to avoid morale from collapsing, Caesar also started rotating his troops to ensure they remained rested and alert.

Moreover, he made use of deceptive tactics, such as feigned retreats and sudden charges, which lured Pompey’s soldiers into overextending themselves.

This kept Pompey off balance and forced him to remain on the defensive, and unable to launch a coordinated counterattack. 

Pompey’s strategy at Dyrrachium relied primarily upon leveraging his superior numbers and strong defensive position to wear down Caesar’s forces.

He had chosen to establish his base near the coastal city because he knew that its location offered both strategic depth and access to vital supply lines from the sea.

Pompey wanted to avoid a direct confrontation on unfavorable terms. Instead, he aimed to use the surrounding terrain to his advantage and try to force Caesar into a prolonged siege that would strain his resources.

If this worked, Pompey believed he could make his enemies vulnerable to a counterattack when the opportunity arose. 

Pompey commanded a well-equipped army, with an estimated strength of 30,000 to 40,000 men, including experienced veterans and newly recruited troops.

His commanders, such as Metellus Scipio and Afranius, were tasked with maintaining the fortifications and ensuring that the troops were ready for any assault.

Also, Pompey stationed his troops along a series of fortifications stretching from the hills surrounding Dyrrachium down to the coastline.

These positions allowed him to monitor Caesar’s movements closely and respond quickly to any attempt at breaching the defenses. 

These fortifications were carefully constructed to take full advantage of the natural defenses provided by the landscape.

The city itself sat on a narrow coastal plain, flanked by steep hills and dense forests that made any approach difficult.

So, Pompey ordered the construction of a series of defensive walls and ditches, which formed a layered defense that extended for miles.

These fortifications were reinforced with wooden palisades and watchtowers. 

The Battle of Dyrrachium unfolded over several weeks in the summer of 48 BCE. It was a drawn-out affair, which was mostly a series of maneuvers and skirmishes between Caesar’s forces and Pompey’s well-fortified army.

At the outset, Caesar initially attempted to encircle Pompey’s position by constructing his own extensive line of fortifications.

This would be a double line of fortifications around Pompey’s encampments. This was intended to cut off his opponent’s access to supplies from the surrounding countryside and force a confrontation on his terms.

However, Pompey quickly recognized the threat and ordered his men to construct an additional series of counter-fortifications.

As both sides worked furiously to build their own walls in response to each other, a complex network of trenches and walls developed, stretched across the rugged terrain.

When completed, it created a tactical stalemate that placed both armies under immense strain. What followed was a prolonged and exhausting siege. 

When Caesar’s initial encirclement efforts stalled, he shifted his focus to more targeted assaults on vulnerable sections of Pompey’s lines.

In particular, he instructed his troops to conduct night raids and surprise attacks: actions designed to undermine Pompey’s fortifications and spread confusion among his forces.

Then, on July 9, 48 BCE, Pompey launched a surprise attack on a weak point in Caesar’s lines, hoping to breach the fortifications and deliver a decisive blow.

Pompey’s troops managed to quickly capture one of Caesar’s outer camps, while inflicting heavy casualties and creating a brief opening.

Caesar lost approximately 1,000 men and several cohorts of soldiers. The morale of Caesar’s troops, already under pressure from shortages and exhaustion, suffered further from this defeat. 

After this, the challenges facing Caesar’s forces were becoming increasingly severe.

His food supplies were almost completely spent and there were rumors that some of his men were beginning to starve.

His forces were spread too thin over a large area, making it difficult to reinforce sections quickly when Pompey counterattacked. 

Additionally, Pompey’s ability to maintain his supply lines by sea contrasted sharply with Caesar’s precarious logistical situation, compounding the difficulties Caesar faced.   

Caesar’s ultimate inability to secure a decisive victory at Dyrrachium was a critical setback for his bid to win the war.

He had been hoping to force Pompey into a full-scale battle, where his experienced legions could overpower Pompey’s forces in direct combat.

However, Pompey’s refusal to engage on those terms, combined with his successful defense and counterattacks, forced them to retreat from Dyrrachium all together.

This withdrawal undermined Caesar's position and momentum. However, by doing so, he managed to avoid complete annihilation while preserving the bulk of his forces for future engagements.  

Caesar quickly moved inland, away from Pompey’s fortified positions, to draw his opponent into a more favorable battle on open ground.

Meanwhile, Pompey’s decision to follow Caesar instead of fortifying his position or retreating to a safer location revealed his desire to end the conflict quickly.

This pursuit would eventually lead to the Battle of Pharsalus in August 48 BCE, where the tide of the civil war would decisively turn in Caesar’s favor.

Ultimately, Caesar’s ability to innovate and adapt under pressure was probably the most decisive factor in his overall success during the civil war.