In Othello, what is the name of Othello's lieutenant?

In Othello, Othello’s lieutenant is Cassio. Michael Cassio is a Venetian officer who serves under Othello during the military campaign in Cyprus.

Cassio is respected for his courtesy, education, and military administration, but Othello’s ensign, Iago, resents him because Othello promoted Cassio over Iago. Iago exploits Cassio’s lack of experience with alcohol and provokes a drunken fight, causing Cassio to lose his position.

Desperate to recover his reputation, Cassio asks Desdemona to plead his case with Othello. Iago then twists this innocent contact into supposed evidence of an affair, helping fuel Othello’s jealousy. Cassio survives the tragedy, although he is wounded and becomes part of the final exposure of Iago’s scheme.

A frequent mix-up is Iago, who is Othello’s ensign and antagonist, not his lieutenant. Montano is the former governor of Cyprus, while Roderigo is a Venetian gentleman manipulated by Iago.