This tragedy illustrates another practice of Shakespeare’s. King Lear has a secondary plot, that which concerns Gloster and his two sons.  To make the beginning of this plot quite clear, and to mark it off from the main action, Shakespeare gives it a separate exposition.  The great scene of the division of Britain and the rejection of Cordelia and Kent is followed by the second scene, in which Gloster and his two sons appear alone, and the beginning of Edmund’s design is disclosed.  In Hamlet, though the plot is single, there is a little group of characters possessing a certain independent interest,—­Polonius, his son, and his daughter; and so the third scene is devoted wholly to them.  And again, in Othello, since Roderigo is to occupy a peculiar position almost throughout the action, he is introduced at once, alone with Iago, and his position is explained before the other characters are allowed to appear.

But why should Iago open the play?  Or, if this seems too presumptuous a question, let us put it in the form, What is the effect of his opening the play?  It is that we receive at the very outset a strong impression of the force which is to prove fatal to the hero’s happiness, so that, when we see the hero himself, the shadow of fate already rests upon him.  And an effect of this kind is to be noticed in other tragedies.  We are made conscious at once of some power which is to influence the whole action to the hero’s undoing.  In Macbeth we see and hear the Witches, in Hamlet the Ghost.  In the first scene of Julius Caesar and of Coriolanus those qualities of the crowd are vividly shown which render hopeless the enterprise of the one hero and wreck the ambition of the other.  It is the same with the hatred between the rival houses in Romeo and Juliet, and with Antony’s infatuated passion.  We realise them at the end of the first page, and are almost ready to regard the hero as doomed.  Often, again, at one or more points during the exposition this feeling is reinforced by some expression that has an ominous effect.  The first words we hear from Macbeth, ’So foul and fair a day I have not seen,’ echo, though he knows it not, the last words we heard from the Witches, ‘Fair is foul, and foul is fair.’  Romeo, on his way with his friends to the banquet, where he is to see Juliet for the first time, tells Mercutio that he has had a dream.  What the dream was we never learn, for Mercutio does not care to know, and breaks into his speech about Queen Mab; but we can guess its nature from Romeo’s last speech in the scene: 

                          My mind misgives
     Some consequence yet hanging in the stars
     Shall bitterly begin his fearful date
     With this night’s revels.

When Brabantio, forced to acquiesce in his daughter’s stolen marriage, turns, as he leaves the council-chamber, to Othello, with the warning,

Look to her, Moor, if thou hast eyes to see;
She has deceived her father, and may thee,