In this scene all of Rome is celebrating the Feast of Lupercal, a fertility festival held in honor of the god Lupercus, or Pan; as part of the festivities a foot race is held, in which Marc Antony participates. So, needless to say, there is a very large crowd around Caesar, out for this popular festival. In the throng, the soothsayer calls to Caesar, who, hearing his voice, bids him approach and speak. “Beware the ides of March,” is all he will repeat—a warning of what he has seen in his fortune-telling. Caesar, however, does not take the warning seriously, and instead dismisses the man immediately, stating that “He is a dreamer. Let us leave him. Pass.”
The story of Julius Caesar is well-known today, and was perhaps more well-known in Shakespeare’s time. Thus this event is an example of dramatic irony—the audience knows of Caesar’s fate, and yet Caesar himself disregards the only warning he receives of his forthcoming murder. Similarly, later in the scene Cassius hints to Brutus of his plans to assassinate Caesar, and Caesar, speaking with Antony, notes how he mistrusts Cassius—he “has a lean and hungry look; / he thinks too much. Such men are dangerous.” And yet he asserts, “I fear him not.” Here again is irony, for indeed, if Caesar has anyone to fear, it is Cassius.