Casca, meeting Cicero, describes the marvels visible in the streets that night and suggests that the marvels foretell important events to come. Cicero having left, Cassius arrives to persuade Casca to join the conspiracy to liberate Rome from the threat of Caesar's kingship. When Cinna joins them, Cassius sends him to leave letters where Brutus may find them and be persuaded that his opposition to Caesar is desired by many.