‘Iago continues to fuel Othello’s jealousy, suggesting amorous activity between Cassio and Desdemona,
and inventing Cassio’s “confession” of his conquest of Desdemona. This causes Othello to fall to the ground in a fit.
When he recovers, Iago has another daring scheme in readiness. Othello stands by, unseen, while Iago engages Cassio in conversation.
Othello can see Cassio’s gestures, but cannot hear exactly what is being said.
He totally misinterprets the conversation, as Iago intends him to do.
Othello thinks Iago and Cassio are discussing Desdemona. They are, in fact, talking about Bianca, in grossly unflattering terms.
Othello is convinced. Iago persuades him not to poison Desdemona, but to strangle her in her bed.
Iago volunteers to arrange the murder of Cassio.
Lodovico arrives from Venice, bringing news that Othello is to be recalled from Cyprus and that Cassio will replace him as governor. Desdemona, telling Lodovico of the breach between Othello and Cassio, frankly and innocently mentions the “love” she has for Cassio. Othello strikes her publicly and dismisses her from the company. Lodovico thinks Othello must be out of his mind. Remembering the noble Othello of former days, Lodovico laments the change he sees, and turns to Iago, of all people, for an explanation of the cause.’