On 10 January 49 BC, Julius Caesar led the Legio XIII Gemina in crossing the Rubicon River. Caesar rose to power during his conquest of Gaul, serving as a joint consul with Pompey and Crassus. When ordered to return home and disband his legions by the Roman senate, Caesar feared he would be prosecuted and rendered marginalized politically by his fellow consuls. Disobeying the orders of disbanding his legions, Caesar kept his military force intact and marched against the Senate. Crossing the Rubicon was viewed as a declaration of war, but the Roman populace supported Caesar, who regarded him as a hero of the people and Rome. Despite only marching on Rome with a single legion, the Senate feared Caesar had assembled his entire force to take the Roman capital and fled, leaving a hastily levied force of Italian troops under the command of Domitius to face Caesar.
With Caesar’s army marching deep into Italy, Domitius faced against the renegade Roman troops at Corfinium. Fielding 20 cohorts, Domitius expected Pompey to support his small army against Caesar’s Legion, but when those reinforcements never arrived, surrendered his army. Pompey assembled his forces in Brundisium, before departing to Epirus to flee Caesar’s force. With the absence of Pompey’s force on the Italian mainland, Caesar returned to Rome in December 49 BC and was appointed Dictator. He held the term for 11 days before being elected consul again and then departed with his army for Roman Greece to face Pompey.
With 15,000 soldiers, Caesar embarked for Epirus. Once in Greece, Caesar was able to recruit additional soldiers to supplement his veteran legions, and on 9 August 48 BC his army clashed with Pompey’s in the Battle of Pharsalus. Pompey’s force outnumbered Caesar’s army nearly 2 to 1 but was decisively defeated in the battle. Pompey was forced to retreat from Greece following the battle, heading to Egypt where he met his ultimate fate. The Egyptian king, Ptolemy XIII, made it appear Pompey was welcome but after arriving the Roman general was assassinated. When Caesar arrived in Egypt to confront Pompey, he was presented with the head of his former adversary, which according to Plutarch, left Caesar mourning this great hero of Rome.
Caesar eventually became sole ruler of Rome, having the title of Dictator Perptuo (Dictator in Perpetuity) bestowed upon him in 44 BC. During the Ides of March in 44 BC, Caesar was assassinated by a conspiracy of senators. Octavian, his adopted son, followed in Caesar’s footsteps. With Octavian’s victory in the civil war of the Second Triumvirate, the Roman Republic ceased to exist, and the Roman Empire rose in its ashes.
Look for more information regarding the history of Julius Caesar and the Roman army in the upcoming Strategy & Tactics issue #296 with the article “The Roman Army in the Era of Julius Caesar” and join the conversation on Facebook!