In the opening scene of Othello, two secret acts had been performed.
1. Iago, an officer of low ranks in the Venetian army, and Roderigo, madly in love with Desdemona, are conversing about both their hatred towards Othello. Iago, because of how Othello promoted Cassio to become a lieutenant instead of giving him the position, and Roderigo because of Othello's marriage to Desdemona and how they eloped.
2. Othello and Desdemona have eloped, leaving Brabantio clueless at first and outraged when he found out.
The theme of deception had clearly been brought up, with these two secret acts, and a few other underlying factors to be considered, including:
1. Roderigo feeling deceived by Iago. The former had asked the latter to put him in good favor with Desdemona, in order for her to love him, but clearly this did not take place.
2. Brabantio feeling deceived by his daughter for running away with Othello, and not asking for his permission regarding the matter.
3. Iago confessing that he merely pretended to adore Othello when in fact, he didn't.
These deceptions supercharged the tone of deceit, jealousy, etc. in the play, leaving the reader or the audience cynical and suspicious about everything. This builds up the gravity of the situation the characters are undergoing.
