In Julius Caesar, the Soothsayer warns Caesar to “Beware the Ides of March.”
The warning appears in Act 1, Scene 2, when Caesar encounters the prophetic figure during the Lupercalia celebrations. Caesar hears the danger but does not treat it as a serious command. The brief exchange establishes the play’s atmosphere of political anxiety and foreshadows the assassination that occurs on March 15.
The Soothsayer is not Calpurnia, Caesar’s wife, although Calpurnia later has a warning dream and urges him not to go to the Senate. Cassius and Brutus are conspirators, not the speakers of this famous line. Their political actions help bring about Caesar’s death, but they do not deliver the warning.
Shakespeare’s phrase draws on the Roman calendar. The Ides fell on the fifteenth day of March, May, July, and October, and on the thirteenth day of the other months. Caesar is assassinated on the Ides of March in 44 BC, making the phrase one of drama’s best-known examples of foreshadowing.