ANSWER: Othello is set in Venice, presumably sometime in the latter half of the sixteenth-century. Venice was at war with the Ottoman empire between 1570 and 1573, so the play’s reference to the threat of an attack on Cyprus could reflect a setting sometime during this period. Venice was well-known as an early example of what might later be called a multicultural city, boasting a much greater diversity of ethnicities and religions amongst its inhabitants than most other European cities could. Othello is identified in the play’s subtitle as a “Moor”: a term most typically used in this period to signal someone who was either of African descent, Muslim faith, or both. Whatever the precise details of Othello’s racial and religious identity, they are clearly enough to provoke anxiety when Iago torments Brabantio by referring to Othello as “an old black ram” (1.1.) and a “Barbary horse” (1.1.). While Brabantio is outraged that his daughter has married a man marked as an outsider, Othello has also clearly gained a significant amount of prestige and respect in Venice since the Duke trusts him with the crucial military defense of Cyprus. As a setting, Venice serves Shakespeare’s needs of a place where a non-European, and potentially non-Christian, man could both hold significant authority but still be distrusted.
Answer: It doesn't really specify on who but more on "what". It looks like it was a Republican government at the times (the invasion between the Ottoman Empire and the Christian Republic of Venice)
