With all of Rome against him, the chances of Julius Caesar winning the civil war, a war which he himself had caused by crossing the Rubicon, were considerably low. Pompey, Caesar’s former ally and now rival, was supported by the Senate. It looked bleak for Caesar.
But Pompey and the Senate saw Rome as undefendable, and so retreated to Capua, in the South of Italy – 11500 soldiers, made up of two legions and levied cohorts commanded by Lucius Ahenobarbus. Caesar moved South to meet Pompey, who fled further, this time towards Brundisium, and across the sea to Epirus, in the East.
Ahenobarbus’ thirty cohorts swore allegiance to Caesar’s armies, swelling his ranks as the Senate fled. In 27 days, Caesar pacified the entirety of Roman Hispania (Spain). When he returned to Rome in December, 49 BC, Caesar was appointed Dictator for eleven days, until he became consul. Mark Antony took place as Caesar’s Master of the Horse.
Seven legions in tow, Caesar crossed the Strait of Otranto to the Gulf of Valona, prompting Pompey to force a decisive battle with Caesar. This resulted in the Battle of Dyrrhachium on 10 July 48 BC, which saw one thousand of Caesar’s veterans slaughtered. He retreated south.
Pompey believed this to be the feint to a trap, and did not pursue, losing the advantage. Near Pharsalus, the two met again, and Caesar conclusively defeated Pompey’s much larger army. With no army and deteriorating support, Pompey had no option but to flee, this time to Egypt.
In Egypt, Pompey was assassinated by an officer under King Ptolemy XIII; Caesar had followed the Pompeian army to Alexandria, where he became involved with the Egyptian dynastic struggle on the side of Cleopatra (as Ptolemy had had Pompey killed). Caesar was besieged at Alexandria – which resulted in the greatest loss of knowledge history has ever known, with the Great Library being burned to the ground – but was relieved by Mithridates, allowing the pair to defeat Ptolemy’s army, and install Cleopatra as ruler of Egypt. Here, Caesar’s only biological son was born – Ptolemy XV ‘Caesarion’ Caesar.
Later in 47 BC, Caesar went to war with Pharnaces II, a client king of Pompey who, taking advantage of the circumstances, attacked Roman-friendly client kings, conquering their land. Pharnaces would have continued if it had not been for the rapid approach of the Romans, which resulted in the Battle of Zela.
Of this battle, only a single comment can be made… Veni, vidi, vici. I came, I saw, I conquered.
Pharnaces died in battle against Asandar, a former governor of his who had sided with Caesar.
In 46 BC, Caesar annihilated the forces of Metellus Scipio, Cato the Younger and Juba at Thapsus. All three Senators committed suicide. The Battle of Munda in 45 BC saw the quelling of the remnants of the opposition, leaving Julius Caesar as sole ruler of Rome.