He manipulates his wife Emilia, Desdemona's lady-in-waiting, into taking from Desdemona a handkerchief that Othello had given her; he then tells Othello that he had seen it in Cassio's possession. Once Othello flies into a jealous rage, Iago tells him to hide and look on while he (Iago) talks to Cassio. Iago then leads Othello to believe that a bawdy conversation about Cassio's mistress, Bianca, is in fact about Desdemona. Mad with jealousy, Othello orders Iago to kill Cassio, promising to make him lieutenant in return. Iago then engineers a fight between Cassio and Roderigo in which the latter is killed (by Iago himself, double-crossing his ally), but the former merely wounded.