The plot of the libretto differs greatly from Shakespeare's play in that it takes place wholly in Venice, not mainly on Cyprus, and the dramatic conflict develops in a different manner. The role of Iago is much less diabolical than Shakespeare's play or Verdi's 1887 opera "Otello", which was also based on it. Shakespeare derived his play from the story "Un Capitano Moro" ("A Moorish Captain") by Cinthio, a disciple of Boccaccio, first published in 1565.In further contrast, the role of Roderigo, a sub-plot in Shakespeare and Verdi, is very prominent in Rossini's version—some of the most difficult and brilliant music being assigned to the character Rodrigo. The roles of Otello, Iago, and Rodrigo are all composed for the tenor voice.