After Cassius and Brutus have met with Antony's side in a parley, they go back to their own camp. What irony does Cassius reaveal?in Julius Caesar
After the parley with Antony and Octavius, Cassius reveals two bits of irony.
First, he reveals that it's his birthday. Later, in scene three, he says, "This day I breathed first: time is come round,/And where I did begin, there shall I end;/My life is run his compass." Cassius finds it ironic that he is probably going to die on the same day that he was born.
Second, Cassius tells Messala that he has changed his mind about omens. Earlier in the play, Cassius refused to believe the strange happenings around Rome (fire falling from the sky, the earth trembling, etc) had anything to do with the assassination attempt he was planning. Now that he is less confident in his endeavors, he interprets the scavenger birds he saw overhead (crows and ravens) as a bad sign--as a sign they will lose the upcoming battle. It is ironic that Cassius is so fickle in his opinions of the omens depending on what state of mind he is in. He was the one who was strong enough to convince Brutus and others to help him with his "noble deed" but after it was completed, he is not as strong-willed.