The theme of racism is strongly depicted in William Shakespeare's Othello. It depicts the attitude of European society towards those that were different in colour, race and language. In Europe, people of white complexion were the majority and all other races were considered to be less important and inferior.
There are several characters in this that play portray this mentality. These characters include Brabantio, Roderigo and Emilia. But by far, the face of racism in this play is that of Iago, who makes his intentions crystal clear in his soliloquy where he states I hate the Moor, (I, iii, 379). Throughout the play, Iago lays forward a number of reasons for his hatred, which leads to the ruin of most of the characters.
It is most likely that the main reason behind Iago's hatred of Othello is the colour of his skin. Similar to many other people of his time, Iago would have had little or no racial tolerance for others, and thereby saw Othello as an outcast that had risen to success - which is a factor contributing to another of his reasons for hatred - jealousy.
From the very first act of this play, and indeed the very first scene, Iago hurls racial insults at Othello, an example of which is ...very now, an old black ram is tupping your white ewe (I, i, 89-90) - A statement that has both racist and vulgar connotations, as well as referring to Othello as a Barbary horse (I, i, 112) - Which is degrading him to the level of a filthy animal.
As was mentioned before, jealousy is also one of the reasons behind Iago's hatred. His behaviour and speech indicates clearly that he is jealous of success (Othello becoming a general, Cassio becoming his second-in-command)...