How Othello's Character Changes

Nadia
In the play Othello, by William Shakespeare, the title character is a valiant hero who is in love with his beautiful bride, Desdemona. The play’s villain, Iago, destroys this love by feeding Othello vicious lies about Desdemona, causing Othello to slowly go mad. By the end of the play, Othello, in a fit of jealous rage, murders his wife. This significant change in Othello’s character is not sudden; rather, it is a gradual transformation that takes place after a series of events that occur throughout the play. Othello’s character undergoes a significant change due to a series of events at the hands of Iago, the play’s antagonist to enhance the fact that even a valiant heroes can become corrupt.
In the beginning of the play, Othello adores

I will a round unvarnish 'd tale deliver
Of my whole course of love; what drugs, what charms,
What conjuration and what mighty magic,
For such proceeding I am charged withal,
I won his daughter. (1.3.79-99)

Othello’s actions in this scene show is undeniable love for his wife, he knows that he could be killed or fired for expressing his feelings for Desdemona. Othello also trusts his second in command, Cassio, very much. He admires him very much and thinks of him as a brother. Othello has a close relationship with Iago, as well. He trusts him and believes the lies that he tells about Desdemona. In one scene, Iago tries to protect Othello from Brabantio, even though he is the one who told him that Desdemona and Othello married in the first place. He exclaims:
He prated,
And spoke such scurvy and provoking terms
Against your honour
That, with the little godliness I have,
I did full hard forbear him. But, I pray you, sir,
Are you fast married? Be assured of this,
That the magnifico is much beloved,
And hath in his effect a voice potential
As double as the duke 's: he will divorce

Othello starts to believe Iago’s lies about his friends and wife, leading Othello to change his behavior towards his closest allies. Iago instigates a fight between Cassio and Montano, and Othello must take charge of his soldiers, he says: Thy honesty and love doth mince this matter,
Making it light to Cassio. Cassio, I love thee
But never more be officer of mine. (2.3.210-213)

Othello makes the decision to fire Cassio, and things get worse when Iago makes his wife, Emilia, steal Desdemona 's handkerchief. Iago plants the handkerchief in Cassio’s lodging, and has a conversation with Othello about Cassio, saying:
IAGO Nay, but be wise: yet we see nothing done;
She may be honest yet. Tell me but this,
Have you not sometimes seen a handkerchief
Spotted with strawberries in your wife 's hand?
OTHELLO I gave her such a one; 'twas my first gift.
IAGO I know not that; but such a handkerchief--
I am sure it was your wife 's--did I to-day
See Cassio wipe his beard with. (3.3.443-449)

By telling Othello this, Iago makes Othello even more jealous and curious. Othello starts to become irrationally jealous and extremely violent, especially around Desdemona. In this scene, we see the exchange between the couple:

DESDEMONA