Othello knew that Brabantio would be horrified at the mere thought of giving his daughter to a Moor; and so he very easily persuaded Desdemona to enter into a secret marriage with him.
Brabantio was filled with great indignation when he was afterwards told of their union, and, accusing Othello of having resorted to magic spells in winning the affections of the maiden, he took the whole matter before the Duke of Venice; but when the royal judge had listened to Othello's simple tale of love, and Desdemona's sweet declaration of trust in her husband, he announced that their mutual affection had come about in a perfectly natural way, and that no magic had been used.
So Brabantio was obliged to give his daughter to her lawful husband; and almost immediately after the case had been settled, Othello, as leader of the Venetian Army, was sent on a military expedition to the island of Cyprus.
The Moor departed first, leaving Desdemona to follow in the care of his lieutenant, Cassio; and upon their arrival in Cyprus great rejoicings were held.
Now, Othello had another confidential officer, whose name was Iago, and who served him as his Ancient; and this Iago, who was of an envious, cruel, and bitter nature, had a grudge against Cassio, because the latter had been made lieutenant, a post he coveted himself. He also envied the happiness of Othello; for he himself had cherished a passion for Desdemona, and had been filled with bitterness at her preference for the noble Moor. He therefore determined to bring Cassio quickly out of favour with his master, so that he himself might be advanced; and with this object he devised the cunning and cruel plan of making Othello believe that Cassio was the lover of Desdemona, and thus, by bringing misery on all, to satisfy his vengeful and envious nature.
He first of all led the unsuspecting Cassio into the folly of drinking too deeply one night when on guard in the camp; and then, as squabbling arose in consequence of this, he brought Othello upon the scene to learn the cause of the disturbance.
The Moor was so displeased with the foolish conduct of Cassio that he would not permit him to be his lieutenant any longer; but the cunning Iago was not yet satisfied, and he determined to use the disgraced officer still further, in order to bring woe upon Othello himself, whose happiness in the possession of the lovely Desdemona he was so eager to destroy.
He therefore now pretended to be Cassio's friend, and advised him earnestly to ingratiate himself with the Lady Desdemona, who might be induced to intercede with her husband on behalf of the erring officer; and as Iago's own wife, Emilia, was chief lady-in-waiting to Desdemona, it was quite easy for the necessary interviews to be arranged.
The gentle Desdemona, with never a thought of evil, received Cassio very kindly, and promised to plead for him with her husband, saying: