"the outburst of rage engendered in Othello by a lost handkerchief"

   In William Shakespeare's Othello, Desdemona's handkerchief is the chief tool Iago uses to bring about his commander's ruin.  Given by Othello as a token of love, it is misplaced in Act III, Scene 3, allowing Iago to manipulate it into the hands of Cassio, an honourable lieutenant.  This becomes the sole kernel of evidence around which Iago builds his relentless insinuations that the two are having an affair, ultimately leading Othello to murder his beloved.

 

Fully annotated online text of the play