Act III sees Othello's jealousy and insecurity grow as Iago continues sowing seeds of doubt. Desdemona advocates for Cassio to be reinstated, fueling Othello's suspicions. Iago manipulates Othello into believing Desdemona has been unfaithful using the lost handkerchief as "proof." Othello vows revenge while losing his grip on reason and language. Chaos and emotion overtake the once orderly general as his tragic downfall progresses.