This play, a study in the philosophy and psychology of evil, was written especially for the new king of England, James 1, in 1605-6. Various references to the Gunpowder Plot play a significant part in it, especially the porter and his 'equivocators'. "Fair is foul and foul is fair", is another reference to the time, meaning, all is fair in love and war, with reference to Macbeth, the play relates this anecdote faithfully. Shakespeare included the witches, as King James had a particular fascination for them, and had written his own treatise on the matter years hence. Later, as Macbeth visits the witches again, their vile concoctions and brews, graphically illustrated on the stage with blood and gore aplenty,he is suffused by the horror of it! As are we, for these creatures, as Banquo put it, "Are not of the Earth, but are on it!" Elizabethan audiences, not now, were only too aware of the treatment handed down to supposed witches, as superstition ranked highly then, and many were witness to the drowning and burning of lonely old women, hatefully identified as witches.