Who Led the Conspiracy to Assassinate Julius Caesar?

illustration of the assassination of Caesar

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We really don't know who led the conspiracy, but we have a good idea, especially since Brutus and Cassius were the leaders after the fact at Philippi.

Gaius Longinus Cassius claimed the honor. He said that since he had tried to assassinate Julius Caesar at Tarsus in the spring of 47 B.C., that made him first conspirator, according to J. P. V. D. Balsdon [cf Cicero Philippics 2.26 "[Cassius was] a man who even without the assistance of these other most illustrious men, would have accomplished this same deed in Cilicia, at the mouth of the river Cydnus, if Caesar had brought his ships to that bank of the river which he had intended, and not to the opposite one."].

Cassius is not the only one who claimed to have tried to assassinate Caesar earlier. Balsdon says that Mark Antony had had a last minute change of heart in 45 B.C. when he and Trebonius planned to kill Caesar at Narbo. It was for that reason that Trebonius detained him outside and that Mark Antony wasn't even asked to join the band of perhaps 60-80 senators who wanted Caesar dead.

The first assassin to stab Julius Caesar is another, but less likely candidate for head of the liberatores (the term the assassins used for themselves). He was Publius Servilius Casca.

Marcus Brutus is the preferred candidate for leader, not because he was the instigator, but because his presence and prestige was considered essential to success. Brutus was the (half) nephew of the martyred Cato. Brutus was, likewise, an idealist. He was also married to Cato's daughter Porcia, probably the only woman in the conspiracy, although she was not an assassin.

Ancient Historians on the Conspiracy and Assassination of Julius Caesar


  • "The Ides of March, by J.P.V.D. Balsdon, Historia, 1958.
  • "The Ides of March: Some New Problems," by Nicholas Horsfall, Greece and Rome, 1974.
  • "The Conspiracy and the Conspirtors," by R.E. Smith, Greece and Rome, 1957.
  • "Existimatio, Fama, and the Ides of March," by Zvi Yavetz,Harvard Studies in Classical Philology, 1974.