Julius Caesar, returning victorious to Rome from foreign wars, is escorted to the Capitol by enthusiastic citizens for a public celebration. On the way, he is warned by a soothsayer to “beware the Ides of March.” At the celebration, the citizens, through Mark Antony, offer Caesar the crown. Three times he refuses.
However, a group of conspirators, headed by Cassius, is disturbed by the power Caesar has gained and the idea that he might seize total power. To help their cause, the attempt to persuade Brutus, a good friend of Caesar and a man well-known for his honesty, that the welfare of Rome demands Caesar’s death.
That night, a tormented Brutus debates with himself whether to join the conspiracy. His fear that Rome may lose its freedom wins out over his admiration for Caesar, and at last he agrees to join with Cassius and the other to assassinate Caesar the next day.
The next morning is March 15, the Ides of March, and Calphurnia, Caesar’s wife, complains that she has had frightful dreams and has heard of evil omens. She urges her husband to avoid danger and stay home from the senate that day. After arguing that he will appear frightened or ignoble by staying home, Caesar finally gives into his wife and consents to staying with her. The conspirators, however, come to his house, acting as friends and supporters, and succeed in inducing him to accompany them, instead, to the capitol.
In the capitol, at the foot of the statue of Caesar’s old enemy, Pompey, the conspirators surround Caesar on the pretext of discussing business with him—and each, in turn, stabs him. Seeing Brutus’s thrust, Caesar exclaims “et tu, Brute” (you too, Brutus) and dies. Mark Antony, Caesar’s friend, confronts the conspirators; and they seem to convince him that their actions were right, and they agree that Antony may speak at the funeral, as long as he does not condemn the conspirators.
Brutus speaks first at the funeral and says that love of Rome alone made the murder necessary, a sentiment which is hailed with enthusiasm by the populace. Antony follows, praising Caesar, while calling Brutus and the conspirators “honorable men.” He so cleverly twists the argument, without blaming the conspirators, that the crowd, a moment before cheering Brutus, turns in anger against the conspirators, who are forced to flee from the city. Indeed things become so chaotic that a poet named Cinna, who had nothing to do with Caesar’s death, is killed by the mob just because his name is the same as one of the conspirators.
In Rome, the ruling triumvirate of Antony, Octavius, and Lepidus formed after Caesar’s death plot revenge and organize a military force to fight the armies of Brutus and Cassius. The opposing armies gather on the battlefield of Phillipi.
Meanwhile, the relationship between Cassius and Brutus has deteriorated into an open quarrel. After the argument is settled, Brutus confides to Cassius that his wife, Portia, has committed suicide. Later that night, unable to sleep, Brutus is stunned to see Caesar’s ghost, who warns that he will meet him again at the battlefield of Philippi.
That morning the armies meet and the forces of the triumvirate are victorious. Unwilling to endure defeat and dishonor, both Cassius and Brutus kill themselves. Antony vows to give Brutus the funeral of a noble Roman and calls him “the noblest Roman of them all,” since he was the only conspirator whose motive was not envy of the powerful Caesar.