Otello dismisses the others, and declares that he now believes that Desdemona may be deceiving him (Otello: "Ora e per sempre addio sante memorie" / "Now and forever farewell, holy memories"). Iago returns, and the jealous Otello demands proof of Desdemona's infidelity. Iago says that once, when he and Cassio were sleeping in the same room, he heard Cassio talking to Desdemona in a dream. In the dream, says Iago, Cassio told Desdemona that they must be careful to conceal their love. (Iago: "Era la notte, Cassio dormia" / "It was night, Cassio was sleeping".) Iago says that dreams don't prove anything, but remarks that he saw Cassio carrying Desdemona's strawberry-embroidered handkerchief just the day before. Otello swears vengeance on Desdemona and Cassio, and Iago joins him in his vow (Otello, Iago: "Sì, pel ciel marmoreo giuro" / "Yes, by the marble heavens I swear").