Entry 3-Iago's motivation

It's really hard to pinpoint what Iago's motives were, as there is little to no evidence as to what Iago was trying to accomplish. I can theorize, however, that Iago might've been jealous of Othello's succes as a General, his nobility, or even his positive associations with the Brabantio, and the fact that Brabantio held Othello very high as a person.