Throughout the play, Iago is portrayed as a very jealous and angry person. He is desperately seeking revenge on a situation he has no control over. His vengeful mentality is rooted in his jealously of Cassio, for being promoted to lieutenant and anger with Othello for promoting Cassio when Iago felt he was more qualified for the position. Instead of talking to Othello about the decision for the position of lieutenant, Iago decides to set up Cassio so that Othello thinks his wife, Desdemona, is having an affair with him. During Act IV, Iago is presented with the perfect opportunity to stage Cassio’s admittance about the affair Othello thinks he and Desdemona are having. Through some carefully thought-out words and actions, Iago is able to manipulate others to do things in ways that benefit him.
             Iago’s first move towards manipulating Othello is by upsetting him. Iago does this by speaking of kissing in private, an act he deems Cassio and Desdemona have done. Iago continues through the conversation with Othello infuriating him into thinking that Cassio and Desdemona have spent time together in the same bed Othello and Desdemona share. Because Othello is upset by these remarks, he falls into an epileptic seizure. While Othello is in the trance, Cassio arrives in the scene. This gives Iago the chance to send Cassio away and have him return later after Othello is well and gone. He says to Cassio, “I would on great occasion speak with you” (IV, i, 60). Iago wants to speak to Cassio about his and Bianca’s relationship. However, when Othello awakes from his trance, Iago tells Othello that he will get Cassio to tell the story of his affair with Desdemona.
             Iago manipulates what Othello can see and hear by placing him away from Iago and Cassio. But Othello is only “seeing” and “hearing” from Iago’s perspective; he substitutes evidence of things seen for a belief ...