None of Iago's handkerchief trickery in the play 'Othello' by William Shakespeare could have been possible without Emilia - she gets hold of the handkerchief for Iago. She is Iago's wife and is very important in the sense that she turns out to be the only character that Iago cannot manipulate, when she reveals her true feelings at his real use for her mistress's property. As Iago's wife, Emilia gets to sail on the ship with him and the wedding couple in her role as handmaiden to her mistress Desdemona. In an effort to please her husband, she agrees to recover the handkerchief - but she doesn't know what he wants it for. When she finds out how the trickery contributed to Desdemona's death (and her unwitting part in it) she will not keep quiet about it.
Iago goes to great lengths to trick Othello into thinking Cassio was having an affair with Othello's new bride, Desdemona. Iago calculates each and every step that he will take in order to lead to Othello's demise. First, he must make sure that Cassio falls out of good favor with Othello. He does this by creating a fight between Roderigo and Cassio. Othello learns of this fight and essentially strips Cassio of his rank as lieutenant. Cassio is distraught and turns to Desdemona for help. Desdemona ensures Cassio that she can persuade her husband into restoring his faith in Cassio, and proceeds to "talk him up" to Othello. Meanwhile, Iago puts it in Othello's ear that Cassio and his wife are having an affair. The fact that Desdemona insists that Cassio is noble and deserving of his old rank makes Othello doubt that his new wife is indeed being faithful. When Desdemona offers her handkerchief to Othello, the first gift he had ever given her, he says it is too small to fit on his forehead and he drops it on the floor. It is picked up by Emilia, who mentions that Iago has been asking her to steal this for him. She gives it to Iago, and he plants it in Cassio's room. He then tells Othello that Cassio has been whipping the handkerchief out for all to see, bragging about his affair with Othello's bride. Othello demands to see Desdemona's handkerchief. When she admits that she cannot find it, Othello falls into a jealous rage.