What is important about Lodovico in Othello?

Lodovico is a minor character in this excellent tragedy,
and his main role is in Act IV scene 1. However, it is important not to simply dismiss
the role of minor characters such as Lodovico, and part of an attentive student's job is
to consider how they are used and what function they perform in the play as a
whole.

Lodovico then is a kinsman of Desdemona, and he
brings news to Othello in Act IV scene 1 that he is to return to Venice, by the order of
the Duke, and leave Cassio in command. Lodovico innocently asks after Cassio, which,
having heard Iago's suspicions about him, annoys Othello. That it is his wife that
responds to Lodovico's question annoys him even further. When Othello strikes his wife
because of her happiness at leaving Cyprus, Lodovico is horrified, and this shock is
only increased when he accuses her of being a poisonous, unfaithful woman. Lodovico thus
acts as a kind of commentary on how Iago has succeeded in changing Othello from the
beginning of the play. Note what he says about what he has
seen:

Is this
the noble Moor whom our full senate

Call all in all
sufficient? This is the nature

Whom passion could not
shake? whose solid virtue

The shot of accident nor dart of
chance

Could neither graze nor
pierce?

Such a speech draws
our attention to how Othello has become subject to passions that now dominate him,
whereas before he was famed for his self-control and his dominance of his passions.
Lodovico thus acts as a reminder of how much Othello has changed, and also this event
foreshadows the tragic end of the play. It is only one step up from hitting to murder,
after all, and Lodovico, like the audience, has observed Othello's anger and murderous
passion in this scene.