Iago is a fictional character in Shakespeare's Othello (c. 1601–04). The play's main antagonist, Iago is the husband of Emilia, who is in turn the attendant of Othello's wife Desdemona. Iago hates Othello (who is also known as "The Moor") and devises a plan to destroy him by making him believe that his wife is having an affair with his lieutenant, Michael Cassio.
The role is thought to have been first played by Robert Armin, who typically played intelligent clown roles like Touchstone in As You Like It or Feste in Twelfth Night.
The character's source is traced to Giovanni Battista Giraldi Cinthio's tale "Un Capitano Moro" in Gli Hecatommithi (1565). There, the character is simply "the ensign". Iago is a soldier and Othello's ancient (ensign or standard bearer).
Read more about Iago: Origin, Role in The Play, Description of Character, Motives, Other Versions of The Character