Born into a Patrician family, he became Pontifex Maximus (High Priest) in 63 bc as part of a deal with Pompey and Crassus, the so-called ‘First Triumvirate’; as consul in 59 he obtained the provinces of Illyricum and Cisalpine and Transalpine Gaul. A superb general, able to inspire loyalty in his soldiers, he subjugated Gaul, crossed the River Rhine, and made two expeditions to Britain. He refused to surrender command until he had secured a second consulship for 48 bc, which would render him immune from prosecution by his enemies, by now including Pompey. When the Senate delivered an ultimatum in January 49, he crossed the Rubicon, took Rome, and defeated Pompey at Pharsalus in 48. He demonstrated clemency by permitting those who wished to do so to return to Italy. After campaigns in Asia Minor, Egypt, Africa, and Spain he returned to Rome in 45.

He governed Rome as dictator, finally as ‘perpetual’ dictator. His wide-ranging programme of reform, which included the institution of the Julian calendar, reveals his breadth of vision, but he flaunted his ascendancy and ignored republican traditions. A conspiracy was formed, led by Brutus and Cassius, and he was assassinated on the Ides (15th) of March 44.