In Shakespeare's "Othello" we are told a tale in which there is much manipulation amongst a group of nobleman for the potential of various personal gains. Whether one man wanted another man's wife, or a man wanting a political promotion, most characters were somehow involved in lying, stealing, and murdering to get their goals, no matter how ruthless the manner they went about doing it. Regardless of all the actions that took place in "Othello", the driving force behind all of them was the jealousy of a man named Iago.
The theme of jealousy is much apparent to even the casual reader as the words "jealous" and "jealousy" appear in the play 16 times, which mostly occur in the crucial act III, scene III where Othello confronts Desdemona. Yet the first direct reference to Iago's jealousy occurs in the soliloquy in act II, scene I; where he muses on a plot to ruin Othello, "Or, failing so, yet that I put the Moor At least into a jealousy so strong That judgment cannot cure." Yet at the same time Iago was also planning a way to "Make the Moor thank me, love me, and reward me for making him egregiously an ass." His rising jealousy and vindictiveness becomes more and more apparent as the play progresses.
While the primary cause of Iago's jealousy comes from the anger of being passed over on a promotion, an overlooked factor is the fact that Othello may have been also sleeping with Iago's wife. This too is pointed out in Act II, Scene I: "For that I do suspect the lusty Moor Hath leap'd into my seat: the thought whereof Doth, like a poisonous mineral, gnaw my inwards; And nothing can or shall content my soul Till I am even'd with him, wife for wife" While earlier his anger for being passed over a promotion may have seemed overblown, it may have very well just been a small factor in his rage. The idea of a sexual relationship between his wife Emilia and Othello could have played a strong role in the course of action that he took. Again, Iago makes it very clear that his jealousy is driving him to the point of insanity as it is slowly gnawing him away from the inside. By act III, scene III Iago plays on Othello's fears of his wife's infidelity "O, beware, my lord, of jealousy; It is the green-ey'd monster which doth mock The meat it feeds on: that cuckold lives in bliss Who, certain of his fate, loves not his wronger; But O, what damned minutes tells he o'er Who dotes, yet doubts, suspects, yet strongly loves!" The jealousy has taken him over fully at this point, almost like that of a spreading cancer, a spreading cancer that has taken over a victim's ability to use reason and take a "rational" approach to their feelings of jealousy. Iago simply is trying to rid himself of his jealousy by transferring it to the man he despises.
By the time the play ends, Iago achieves his goals. He convinces Othello that Desdemona is being unfaithful, and has her killed. Othello then finds out the truth and kills himself. Yet in the end, Iago is arrested, and the reader cannot help but wonder if his lust for vengeance was indeed worth the damage done and the cost he has to pay for it, his own life.