On the outbreak of the civil war, DeIotarus naturally sided with his old patron Pompey, and after the battle of Pharsalus escaped with him to Asia.
In the civil war between Caesar and Pompey Pollio sided with Caesar, was present at the battle of Pharsalus (48), and commanded against Sextus Pompeius in Spain, where he was at the time of Caesar's assassination.
After the battle of Pharsalus he joined his father in abusing his uncle as responsible for the condition of affairs, hoping thereby to obtain pardon from Caesar.
Was able to effect a junction with this force and descended into the plain of Thessaly, where at the battle of Pharsalus he was decisively defeated and fled to Egypt, pursued by Caesar, who learnt of his rival's murder on landing at Alexandria.
Deputy-governor of Italy during Caesar's absence in Spain (49), second in command in the decisive battle of Pharsalus (48), and again deputy-governor of Italy while Caesar was in Africa (47), Antony was second only to the dictator, and seized the opportunity of indulging in the most extravagant excesses, depicted by Cicero in the Philippics.