In the opening scene, Iago complains to Roderigo that Othello, his Commander, has passed him over to promote the handsome young Cassio to be his Lieutenant. He vows to get revenge. Iago first asks Roderigo to tell Desdemona’s father, Brabantio, that his daughter has left to marry Othello, a marriage Brabantio opposes because Othello is a Moor. Brabantio confronts Othello, and they take their argument to the Duke, who has summoned Othello to ask him to sail to Cyprus to stop a Turkish invasion. Convinced by Othello and Desdemona that they love each other deeply despite their differences, the Duke gives Desdemona permission to travel with Othello. By the time they reach Cyprus the foreign threat has gone.
Iago manipulates Cassio to make him drunk and gets Roderigo to draw him into a street fight. Iago has his revenge on Cassio when Othello strips Cassio of his rank for misbehavior. Then Iago decides to make Othello believe his wife is unfaithful. He encourages Cassio to ask Desdemona
