confident in what he has already achieved and his exploits that he has done on behalf of the "signiory," and also he is proud of his lineage and his background and the "fortune" that he has gained. Othello comes across in this speech as a very confident man, confident in his own abilities and powers and in what he has achieved. Just as Brabantio is not friendless, so Othello himself has gained influence and he believes that his exploits will "out-tongue" any of the complaints that Brabantio might raise against him.

In Othello, Iago's personal agenda is to destroy Othello and anyone and anything associated with him. Iago is one of the most enigmatic (as in incomprehensible and impenetrable), but nonetheless cunning and calculating characters, ever created. His ability to charm and apparently almost hypnotize everyone with whom he has any contact is what creates suspense and disbelief as he fools one character after the next. Even when there is doubt, he mitigates the circumstances until even a ridiculous notion becomes believable.

Iago persuades Roderigo that he will help him win over Desdemona despite the fact that she is married to Othello and that Brabantio, Desdemona's father, has previously rejected Roderigo's advances on his daughter as being without foundation, reminding Roderigo that she is "not for thee" (I.i.99).

Brabantio learns of his daughter's apparent betrayal from Roderigo's initial shouts, courtesy of Iago, and Iago quickly steps in to take control and convince him that Othello, whom Brabantio has welcomed into his home on many occasions, is nothing more than a "Barbary horse" (I.i.111). It takes quite some persuasion to convince him that Othello did not bewitch his daughter. Accordingly, even though Iago has been proven wrong, it is enough to create suspicion in Brabantio that he even doubts his own daughter's allegiances. He overlooks the fact that his own wife did a similar thing when she married him and warns Othello that "she has deceived her father and may thee" (I.iii.293). It is significant that the very next line mentions "honest Iago" (294).

This comment in line 294 shows that Iago is taken into Othello's confidence very early on and truly believes in the sincerity of "honest" Iago even telling Michael Cassio that he is "most honest" (II.iii.7). This belief together with Iago's "ocular proof" (III.iii.364) will drive the story forward to its tragic end. 

After a dramatic confrontation with Othello and Desdemona, Brabantio bitterly accepts the truth that his daughter has chosen freely to be Othello's wife. He feels angry and betrayed, but he is powerless to impose his will upon her. In frustration, he says to Othello these words about Desdemona:

Look to her, Moor, if thou has eyes to see.
She has deceived her father, and may thee.

He is warning Othello that since Desdemona has deceived her own father, she may very well betray her husband. There is no truth in Brabantio's cruel, bitter comment; his daughter will be a loving and faithful wife. Brabantio's words, however, will play an important role as the drama develops, since Iago is standing nearby when Brabantio warns Othello about Desdemona's possibly deceiving and betraying him in the future.

Observing Brabantio's distress over what he regards as the loss of his daughter in marriage to Othello, as well as the strength and genuineness of Othello and Desdemona's affections for one another, the Duke counsels Brabantio to accept the situation and to make the best of it. The Duke appears to share Brabantio's general opinion that the relationship is an unfortunate development; he describes it as a "mangled matter," and echoes commonplace racist assumptions of the inferiority of dark-skinned people when he says "If virtue no delighted beauty lack, / Your son-in-law is far more fair than black." But he nevertheless urges the old man not to make his loss greater by disowning Desdemona. "Men do their broken weapons rather use / Than their bare hands," he says, an analogy between warfare and domestic relations which eerily foreshadows the play's larger conflict, a career soldier's failed adjustment to married life.

He continues, "When remedies are past, the griefs are ended / By seeing the worst, which late on hopes depended." In essence, he advises Brabantio that there is no use in continuing to regret and suffer over what has already occurred; Brabantio should take comfort in the fact that "the worst" is behind him. But as Edgar tells us in King Lear ("The worst is not / So long as we can say 'This is the worst.'"), this is a fallacious line of thinking. Things can and will become far worse for Desdemona, and Brabantio is right to fear, though he fears for the wrong reasons. Neither he nor the Duke can possibly anticipate the malicious intent of Iago; Brabantio's empty fears that Desdemona has been deceived, spellbound, or corrupted by Othello will be reflected in an unexpected way as Othello is deceived, spellbound, and corrupted by Iago.

The Duke's final bit of advice urges Brabantio to regain what dignity and agency he can by "smiling" in spite of what has happened: "The robb'd that smiles steals something from the thief; He robs himself that spends a bootless grief." Once again, these words are unintentionally relevant to the larger Othello/Iago drama which occupies the remainder of the play. Iago, deprived of his expected military promotion, is the "robb'd" who, with perpetually growing self-satisfaction, steals from Othello everything that he has. Othello, on the other hand, is partly responsible for his own undoing, and "robs himself" in his "bootless" (useless) agony over Desdemona's suspected infidelity.