I need help with the social/historical background in Othello. For example, views on the devil during the Shakespearean period.

One aspect you would want to address would be one of race/ethnicity. Othello was a Moor and dark-skinned, and because he loved and married Desdemona, a white woman, this was controversial.  Her father did not initially approve of their union and Iago, the man who betrayed him and brought out Othello's tragic flaw, makes sure that Othello's ethnicity is emphasized to many people to anger them as it relates to Desdemona.