At first, Julius Caesar seems as though he is in good spirits. He tells Mark Antony to touch Calpurnia because supposedly, “The barren, touched in this holy chase, / Shake off their sterile curse.” Caesar’s wife Calpurnia cannot have children, and the fertility festival of the Lupercal will perhaps grant her fertility.
However, the race is interrupted by a soothsayer who bids Caesar “Beware the ides of March.” Caesar calls him a dreamer and ignores him. We do not see the rest of the ceremony, but we do know that the people cheer for Caesar. Casca later reports that Antony offered Caesar the crown three times, which he refused, perhaps reluctantly. He also apparently had an epileptic fit, or the “falling sickness.” When Caesar returns, Brutus observes, “The angry spot doth glow on Caesar's brow.”
Caesar expresses paranoia. He points to the scheming Cassius in particular: “Yond Cassius has a lean and hungry look; / He thinks too much: such men are dangerous.” He suspects Cassius of being cunning and ambitious. Caesar does not want to seem weak, so he emphasizes that he is not scared of Cassius, only that others would be if they were him. Antony defends Cassius, but Caesar walks away with him and asks him to “tell me truly what thou think'st of him.”
At first, Caesar seems engaged in the ceremony. Then he enjoys the praise and adulation of Antony and the crowd. Maybe his mood changed when the soothsayer spoke, or perhaps it was when he fell. Whatever the case, his cheer turns into anger and suspicion.