has an agenda planned of malevolent proportions with Othello at its target. He is the catalyst of all the destructive happenings within the play starting from the very beginning when he and Roderigo approach the residence of Brabantio in 1.1. He uses crude, racist language to appeal to the senator's traditional beliefs, including such phrases as,
IAGO: Even now, now, very now, an old black ram
Iago even goes so far as to propose that Brabantio's grandchildren will be animals because of his daughter's base marriage with an 'other.'
your daughter covered with a Barbary horse,
you'll have your nephews neigh to you, you'll have
coursers for cousins, and jennets for germans.
Later we are told that Iago's motive is jealousy and he uses the rhetoric of racism to undermine Othello, playing on Brabantio's prejudices to provoke him, even though, as Othello relates later, 'Her father loved me, oft invited me.' [1.3.129] A shock and a few crude comments from Iago is all it takes to make a respected figure turn against a close friend of equal stature simply because of skin colour.
Technically, Brabantio was not legally allowed to nullify his daughter's marriage to the Moor as she was over the age of consent. Culturally, however, he had all the support necessary to challenge the marriage given common racist assumptions of the time, and accuses Othello of sorcery and witchcraft. This means firstly that he is unable to imagine his daughter wilfully deceiving him, an understandable reaction given her past dutiful behaviour, 'so tender, fair and happy' [1.2.66] and the nature of the patriarchal society in which she lived. Secondly, like Coleridge, he cannot believe she would ever 'fall in love with what she feared to look on
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