The Battle of Dyrrhachium took place on July 10, 48 BC, during the Second Roman Civil War. This battle saw Julius Caesar and Gnaeus Pompeius Magnus (Pompey the Great) clash on the outskirts of Dyrrhachium, present-day Durrës in Albania.
Background
In 50 BC, Caesar was in Gaul, a region he turned into a Roman province, awaiting election as consul. He planned to retain his military command until the election, after which he would request command of the war against the Parthians. However, the Senate, favouring Pompey, declared that Caesar could not run for consul while retaining his military command. Caesar offered to relinquish his command if Pompey did the same, but Pompey refused. As a result, the Senate declared that Rome was in danger and called citizens to arms.
Caesar then gathered his 13th Legion and crossed the Rubicon River, which marked the boundary between Cisalpine Gaul and Roman Italy. As the law prohibited any general from crossing it with an army, this act marked the beginning of the civil war. The following day, he seized Rimini by surprise and ordered Marc Antony to take five cohorts across the Apennines and capture Arezzo. In the meanwhile, Caesar occupied Pesaro, Fano, and Ancona.
News of the successive occupations of Adriatic coast cities and Arezzo soon reached Rome, causing panic among the political elite. Consequently, Pompey abandoned Rome, accompanied by the consuls and the Senate. His strategy was to concentrate his forces in Brindisi to eventually leave Italy. Caesar was greatly disappointed upon learning of these events, as he had not intended to march on Rome but rather sought to negotiate peace with the Senate. Without delay, he headed to Brindisi to negotiate peace with Pompey. However, Pompey rejected the negotiation offer and fled the city.
Still, Caesar did not immediately give chase to Pompey and instead consolidated power in Rome and Italy. He sent legions to Sicily and Sardinia to safeguard vital grain supplies and solidified his control over Rome by appointing Marc Antony as the commander of his forces in Italy. He then set his sights on Spain, where Pompey had considerable support. There, he defeated the forces loyal to Pompey at the Battle of Ilerda.
Returning to Italy, Caesar received news of his appointment as dictator in Rome, and quickly enacted laws aimed at stabilising the capital’s turbulent political and economic landscape. However, his ambition and determination to reunify Rome clashed with practical realities. Facing naval blockades and logistical challenges posed by a hostile Greece, his plans were hindered. His attempts to cross the Adriatic Sea to confront Pompey were thwarted by adverse weather and Pompey’s navy, commanded by Marcus Calpurnius Bibulus.
Nevertheless, Caesar persisted and managed to establish a foothold in Epirus, although at great cost, as Bibulus inflicted heavy losses on his army. Meanwhile, Pompey, perceiving the growing threat posed by Caesar, relocated his main army to Dyrrachium, aiming to consolidate his defences and avoid a direct confrontation until conditions favoured him.
The Battle
Dyrrachium, an important defensive position for Pompey, was secured with the sea at his back and hills in front, making it nearly impregnable. Thus, Caesar had walls and fortifications built to pin Pompey against the sea. Pompey responded with walls and fortifications of his own to prevent any further advancement.
Initially, Caesar held the outlying farmland, but it had been picked clean. Pompey, with the sea to his back, was able to be resupplied by ship. However, as the siege wore on, Pompey found it difficult with the limited land to create enough fodder for his horses, and other supplies became increasingly difficult to maintain. Harvest was approaching, and soon Caesar would have enough food to prolong his position. This caused Pompey to become desperate to break out of the siege.
In mid-summer, Pompey’s luck turned when two Gallic auxiliaries, defected and exposed an unfinished section in Caesar's wall. Pompey seized the opportunity, launching an attack with six legions where Caesar's IX legion held the line by the sea. Heavily outnumbering the Caesarian troops, the Pompeian army broke through the weakened fortifications, causing this segment of Caesar's force to pull back from the onslaught. Although initially successful in the counterattack, Caesar's army began to rout. Realising the potentially disastrous danger his army faced Caesar began to coordinate the withdrawal of his army. Fortunately for him, Pompey believed the retreat was a trap and did not pursue him.
Aftermath
The battle left Caesar’s position significantly weakened. He was forced to withdraw to Apollonia, leaving behind two legions to deceive the Pompeians into thinking his forces remained. When discovered, Pompey sent cavalry in pursuit, but they were repelled in a skirmish with Caesar's rear guard.
As summer approached, Caesar moved to areas untouched by foraging parties, ensuring better logistical support for prolonged operations. In the meanwhile, the Pompeians, buoyed by their victory were divided on their next move. Some urged Pompey to decisively engage and crush Caesar in battle, while others advocated returning to Rome to reclaim the capital. Pompey, however, remained cautious, opting for strategic patience to await reinforcements from Syria and exploit Caesar's vulnerable supply lines. Yet, the initial elation among Pompey's forces soon gave way to overconfidence and internal distrust, pressuring Pompey into seeking a final showdown with Caesar at Thessaly.
