Othello is Shakespeare's Spenserian tragedy, in which the theme of slandered chastity becomes a vehicle for exploring the problems of an allegorica art. Allegory is the mode of selfconscious faith, and Spenser's corpus may be read as a portrait of the artist as allegorist, wrestling first with the burdens of selfconsciousness and then with the burdens of faith. In Othello, Shakespeare compresses and objectifies this struggle. Unlike Spenser, he is not committed to the maintenance of allegory, and so he freely dramatizes the internal weaknesses and external onslaughts that lead to its destruction.
What I am calling the 'Spenserian' quality begins with the chivalric elements in the tragedy. Truly, Othello is a kind of Savage Knight, Desdemona, the absolutely, almost miraculously, worthy lady, and Iago, something of a manipulator like Archimago. But more particularly I would call attention to a specific engagement with Spenserian rhetoric. Consider Cassio's words of welcome to the disembarking Desdemona:
Tempests themselves, high seas, and howling winds,
The gutter'd rocks and congregated sands,
Traitors ensteep'd to enclog the guiltless keel,
As having sense of beauty, do omit
Their mortal natures, letting go safely by
The divine Desdemona.
(2.1.68-73)