Battle of Dyrrhachium (48 BC)

The Battle of Dyrrachium (or Dyrrhachium) on 10 July 48 BC was a battle of Caesar's Civil War in the area of the city of Dyrrachium (in what is now Albania). It was fought between Julius Caesar and the army led by Gnaeus Pompey with the backing of the majority of the Roman Senate. The battle was indecisive but is regarded as a victory for Pompey. The battle preceded the Battle of Pharsalus which was the decisive battle of the Civil War.

Prelude
By the end of Julius Caesar's first year as consul he had accumulated a large list of lawsuits. Roman law gave government officials immunity from prosecution but only during their term of office. Once he became a private citizen Caesar knew he would be vulnerable and instead managed to obtain a proconsul position over the territories of Cisalpine Gaul and Illyricum, with the later addition of Transalpine Gaul. When his five years as proconsul ended Caesar assisted his allies Crassus and Pompey in being elected consuls and his pro-consulship was extended for a further five years. At the end of his term as Governor, having now met the condition on a minimum of ten years between elections as consul, the Senate ordered he resign command of his army. Caesar replied that he would agree to resign his military command if Pompey followed suit. Offended, the Senate demanded he immediately disband his army, or be declared an enemy of the people. In 50 BC, at his Proconsular term’s expiry, the Senate forbade Caesar's standing for election in absentia for a second consulship and because of this, Caesar thought he would be prosecuted and rendered politically marginal if he entered Rome without consular immunity or his army. Caesar responded by marching on Rome and he forced the unprepared Pompey and his allies to flee to Greece, starting the Great Roman Civil War.

Caesar did not immediately give chase to Greece and instead consolidated power in Rome and Italy. He had other problems as well, Pompey had left him with no ships to cross the Adriatic and Spain had begun to mobilize against Caesar. After gathering the remainder of his forces from Transalpine Gaul he marched into Spain and subdued enough of the country that it wouldn't intervene during his campaign against Pompey. He then turned his full attention to Pompey. Having only built half the needed ships Caesar grew impatient and decided to gamble on sending half his army across, and to then have the ships travel back to Rome and transport the remainder. Travel across the Adriatic Sea to Greece would ordinarily be difficult, but was made more so given that it was winter and the sea was treacherous. In addition Pompey's fleet, commanded by Caesar's former junior consul Marcus Calpurnius Bibulus, lay between Caesar and Greece. As it was winter Bibulus was unprepared and Caesar was able to sail through the blockade easily and form a beachhead at Epirus with the first half of his army. Bibulus however was able to block Caesar's attempt to sail his ships back to Italy, burning most of them. Bibulus died shortly after and command fell to Lucius Scribonius Libo.

Caesar's blunder had put him in the worst possible position any army could find itself in. His army had no way to resupply from Rome due to the naval blockade, he couldn't resupply locally as Greece was pro-Pompey and closed their gates to Caesar, and his army was only at half strength. So dire was his situation that he made several attempts to discuss peace with Pompey but was refused at every channel. Realizing he was going to have to fight his way out, he attempted another winter blockade run back to Italy to lead his remaining forces to Greece. His luck was not with him and the rough seas and storms forced him back. However, his Master of the Horse Marc Antony fired up his troops and after several attempts broke Libo's blockade and managed to make it north of Caesar's position. It was now a race against time as both Caesar and Pompey rushed to meet Antony. Although Pompey reached Antony first Caesar was right on his heels and Pompey prudently moved his forces to Dyrrachium to prevent becoming caught between the two forces.

The Siege
Dyrrachium was a strong defensive position for Pompey. His back was guarded by the sea, and at his front there were hills that commanded the immediate area. This made an assault on the position nearly impossible. Caesar instead decided to revisit his Gallic Wars play-book and ordered his engineers to build walls and fortifications to pin Pompey against the sea. Pompey responded with wall and fortifications of his own to prevent any further advancement. Between these two fortifications a no mans land was created which saw constant skirmishes with little or no advancement-- similar to the trench warfare of World War I. Caesar held the out-lying farmland but it had been picked clean and Pompey, with the sea to his back, was able to be resupplied by ship. However, as the siege wore on, their positions began to change. Pompey found it difficult with the limited land to create enough fodder for his horses, and other supplies such as fresh water became more and more 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. By mid summer, though, Pompey had a fortunate stroke of luck. Two Gallic auxiliary were caught stealing the pay from legionaries, but managed to escape to Pompey. With these two men on his side, Pompey was able to discover the weakest point in Caesar's wall. A section to the south of the lines hadn't yet been completed and it was the only viable target for attack.

The Battle
Pompey mounted an attack of six legions against Caesar's line where it joined the sea and where Caesar's IX legion was stationed. 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. Caesar swiftly reinforced the breach with twelve cohorts under Antony and then counterattacked, re-securing part of the wall and pushing Pompey's forces back. Although initially successful, Pompey's forces were simply too numerous and they began to flank Caesar's right wing. This buckled as it was threatened from the rear, and as the wing collapsed, Caesar's army began to rout. At first Caesar personally tried to stem the retreat, but then realised the potentially disastrous danger his army faced and instead began to co-ordinate the withdrawal of his army.

Aftermath
Pompey ordered a halt, believing that Caesar had been decisively beaten, and also suspecting a trap. According to Plutarch, Caesar remarked on that decision saying, "Today the victory had been the enemy's, had there been any one among them to take it."

Caesar next captured the town of Gomphi, allowing his men to resupply and rest and then moved towards Pharsalus, where the decisive Battle of Pharsalus would soon be fought.