1. The backdrop of war. There is a constant threat of war with the Turks.
2. Cassio and Othello used to be fast friends and it was Cassio who helped Othello woo Desdemona.
3. Desdemona eloped with Othello against her father's wishes. She has disobeyed him. The father's rule was the law i n those days.
4. Iago is two faced and exploits the weaknesses of others. He shows honesty to most people, but is really the most nihilistic villain ever.
5. Desdemona is one of the purest, most altruistic women of Shakespeare. She deserves heaven and is given hell instead.
6. The setting is beautiful and exotic. It is tragic that the play ends up spoiling this backdrop with a stage soaked in blood.
7. Friendship and trust are other casualties in the play.
Seven factors that help create the tragic mood in Othello are
- Othello’s tendency towards jealousy when provoked, which becomes the tragic flaw upon which the whole action of the play turns.
- Othello's trust in Iago. Othello does not see until the very end that Iago is determined on his ruin.
- Othello’s inability to see that he has offended Iago by selecting Cassio as his lieutenant
- Cassio’s human qualities, such as a weakness towards drink, which make him an easy dupe for the machinations of Iago.
- The cultural difference between Othello and Desdemona. This makes Othello an easier target for the insinuations of Iago.
- The fact that Desdemona has had to deceive her father to marry Othello, which creates a precedent that helps others imagine she may be deceiving Othello.
- Desdemona's fortuitous loss of the handkerchief, a cherished gift from Othello, just as Othello demands Iago produce concrete proof of her infidelity, and her failure of nerve, when she loses it, but cannot bring herself to tell Othello that she no longer has it.