His smoldering rage now beginning to bubble over, Othello tells Iago to kill Cassio and then angrily confronts Desdemona. Iago manipulates a conversation with Cassio about his courtesan to make it appear to OthelloВ—who is eavesdropping at the behest of IagoВ—that Cassio is talking about Desdemona. Cassio, meanwhile, has given the handkerchief to a courtesan with whom he is intimate. When Othello asks Desdemona about the handkerchief, she tells him that it was lost (which is the truth as she knows it). Later, fortune literally drops Desdemona's handkerchief into Iago's hand he gets the handkerchief from Emilia, who discovered it, plants the handkerchief in Cassio's room, and then tells Othello that he saw Cassio with it. The scenario Iago suggests is that Cassio and Desdemona are having an affair. As Iago and Othello view the scene, Iago plants seeds of doubt and jealousy in Othello's mind concerning Desdemona's fidelity. This accomplished, Iago goes straightaway to Othello so that he can lead him to where Desdemona and Cassio are talking.

Then Iago has Cassio visit Desdemona, saying that an appeal to her might do well to convince Othello to reinstate him. He tricks Cassio into getting drunk, then has RoderigoВ—a former suitor of Desdemona whom Iago has convinced to aid him with the hope of winning Desdemona backВ—pick a fight with Cassio that ends in Cassio's arrest. When they've arrived in Cyprus, Iago sets his machinations to motion. When Othello is posted to Cyprus by the Duke of Venice, Iago escorts Desdemona there to meet him, taking along his own wife, Emilia. Othello has secretly married Desdemona, the beautiful daughter of Venetian senator Brabantio, and Iago determines to use Desdemona as the means of his revenge. Othello, a Moorish general of Venice, has promoted Cassio as his lieutenant Iago, who was hoping for the promotion himself, makes plots against both Cassio and Othello to exact revenge.

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