Comment on how the setting of act 1 scenes 1-3 helps Shakespeare prepare the reader for tragedy.

Setting has a major but not obvious part in Shakespeare's play Othello. The play starts of in Venice, which at the time was up-holded by law and civilization, "This is Venice; my house is not a Grange" as said by Brabantio, chaos has no place in Venice. However, Cyprus was- at the time- the exact opposite of this: It was seen as barbaric and a place devoid of law. The physical change in environment allows the tragedy to unfold in an area prone to destruction. In some ways, the venician law represents the stability of Othello's mind, the move to Cyprus illustrates Othello's descent into madness. 

In venice, Othello has the law on his side, he is not punished by the duke, for marrying Desdemona without her father's permission even though the duke says to Brabantio, "...The bloody book of law, you shall yourself read in bitter letter After your own sense..." This emphasizes that although he is above the law in Venice, in Cyprus there will be no law figurehead to protect him. Also, Othello is a moor and experiences racial derogatory slurs such as, "Barbary horse". Even in Venice- a multicultural society- Othello is an outsider, by going to Cyprus this increases his isolation, making a tragic end inevitable. 

Cyprus itself, also holds some historical background relative to the play. In classical mythology, Cyprus is the mythical home to Aphrodite- the goddess of love and beauty. It is a place where she was "first carried ashore", this is depicted by Shakespeare when Cassius greets Desedemona "...The riches of the ship is come ashore..." this draws parallels to Aphrodite, who was known for her adulterous affairs. This forebodes that the play is centered around Desdemona's fidelity- "...If thou hast eyes to see she has deceived her father, and may thee." At the time, adulterous women were said to have strip their husbands of their masculinity, the possibility of Desdemona cheating on Othello- a man of strength and honor- is enough to ensure a tragic demise.

Sources
http://www.shmoop.com/othello/setting.html
http://www.theatredance.com/othello/comments.html
http://www.sparknotes.com/shakespeare/othello/themes.html