"... Assure thee,
If I do vow a friendship I'll perform it
To the last article ...
Therefore, be merry, Cassio,
For thy solicitor shall rather die
Than give thy cause away!"
Unfortunately, just as Cassio bent to kiss the lady's hand in gratitude as he departed, Othello himself appeared, accompanied by Iago, who cunningly drew his attention to this little scene.
The first faint shadow of jealousy thus crept into the mind of Othello; and when Desdemona presently began to plead for Cassio, although he answered her with fair words, he had already begun to doubt her in his heart.
After Desdemona had retired, Iago ruthlessly continued his wicked scheme of sowing the seeds of doubt in Othello's passionate heart; and the Moor quickly began to suffer the sharp pangs of jealousy, and to cherish a secret wrath against his innocent wife.
"Good name in man and woman, dear my lord,
Is the immediate jewel of their souls:
Who steals my purse steals trash; 'tis something, nothing;
'Twas mine, 'tis his, and has been slave to thousands;
But he that filches from me my good name,
Robs me of that which not enriches him,
And makes me poor indeed!"
said Iago, in a careless tone; and with such enigmatical, subtle words did he set the poison of doubt to work in his master's mind.
Encouraged by the quick success of his villainy, Iago now bade his wife Emilia to procure for him a certain richly worked handkerchief belonging to Desdemona, which had been Othello's first gift to her during their courtship; and Emilia, having no suspicion of treachery, but humbly obedient to her husband's wishes, secured the pretty trifle for him without the knowledge of her mistress. Iago then found an opportunity to make Othello believe that he had discovered this handkerchief amongst the belongings of Cassio, and that it had been given to the ex-lieutenant by Desdemona; and he also added casually that he had often heard Cassio murmur the name of Desdemona with loving emphasis in his sleep.
This announcement filled Othello with such rage that he rushed furiously at Iago, and flung him to the ground; and when next he met Desdemona he broke out into such a stormy tirade that the gentle lady was terrified.
As the days went on the poison of jealousy so artfully administered by the ruthless Iago began to permeate the whole being of the unfortunate Moor to such an extent that he put an evil construction upon the most innocent remarks of Desdemona; and the bewildered wife became very unhappy as she noted the altered behaviour of her husband, being quite unable to account for such a change, since her love for him was as deep and true as ever.
One day there came ambassadors from Venice with letters on State matters for Othello, in which he was bidden to return home; and upon the messengers asking for the absent Cassio, who was to be deputed to the Moor's place, Desdemona replied that the lieutenant had been disgraced, but that she was constantly pleading for his restoration to favour, since she had much regard for him. On hearing these words, spoken in all innocence and kindly feeling for one in trouble, Othello's mad jealousy was roused again; and in a wild outburst of rage he struck Desdemona a rough blow, and then fell to the ground in a convulsive fit brought on by his deep emotion.