Shakespeare's use of these various potentialities of the story and the definiteness of his unifying purpose may both be seen by a comparison with his treatment of the very similar materials furnished by the chronicles for "Richard III." There, following closely the Marlowean methods, he for some reason minimized the motive of remorse emphasized in his sources, and left Richard as conscienceless as Tamburlaine or Barabas. In "Macbeth" the story of ambition is also a story of the temptation, defeat, and remorse of conscience. As in the other great tragedies, Shakespeare informed the old material with the struggle of the human will. At the same time he made the most of the hints in the chronicle that the protagonist was driven by fate or some forces beyond his control. He united with marvelous dramatic tact the destiny tragedy of the Greeks and the villain tragedy of the Elizabethans. As a result the character of Macbeth has its paradoxes that are the despair of the analysts. We do not quite know how far free-will and how far superhuman agencies determined his course. But while the superhuman agencies give his villany a mystery and impressiveness, they never confuse for a moment the distinctions of good and evil. The powers of right and wrong are clearly marshaled, and the triumph of evil leads to anguish as well as to ruin. Shakespeare's transforming and vitalizing use of both the suggestions of Holinshed and the established conventions of tragedy in order to suit this changed purpose is manifest at every turn, but nowhere so transcendently as in his treatment of the supernatural. The ghost that interrupts the banquet is no shrieking revenger, hardly more than a hallucination of the murderer. The invisibility of the ghost to all but the one whom he would frighten or admonish has other examples in the drama, but by 1605 most of the playwrights made their ghosts either melodramatically horrible or vulgarly familiar. In "Macbeth" Shakespeare not only etherealizes the ghost as in "Julius Cæsar" and "Hamlet," but makes him a part of the very mood and temper of the murderer. And similarly, the witches, drawn from Holinshed's hints, represent a supernatural interference very different from that of the furies, devils, or sorcerers usual in the theatre. Some of their stage effects are archaic enough, as the shows of the head, the bloody child, and the monarchs; some, like their vanishing in air, may have been novel on the stage of the Globe; certainly they were all intended to surpass in mere theatrical novelty and effectiveness any of the supernatural or magical creatures of the contemporary drama. Delighting the groundlings and appealing to the current interest in witchcraft, they are none the less essential to the drama, inwrapt in the conception of character. The foul hags of superstition, they seem also to have the attributes of the classical Fates. Novel and effective on the stage, they are the supervisors of Macbeth's destiny.