One of Shakespeare's main interests in writing Macbeth was to examine the nature of kingship, as he had already done in Hamlet and King Lear, written only a few years previously. In order to understand why he was so interested in this topic, we must examine briefly the fascinating early stage history of this play.
Probably written in 1605–1606, Macbeth was first performed for King James I of England less than a year after the infamous Gunpowder plot in which a group of Catholics attempted to blow up the king and the English parliament. A play that concerned treachery and regicide — the killing of a king — was bound to be topical and politically significant. There can be no real question of Shakespeare's wish to flatter a king whose interest in both the supernatural and the nature of kingship are all referred to so strongly in this play. Moreover, James I was descended from Scottish ancestors, the Stuarts, so a play concerning the early kings of Scotland was bound to appeal to him. Shakespeare's only problem was that the Stuarts were descended from Banquo who, as Holinshed's Chronicle makes clear, helped Macbeth murder the king. This explains why, in Shakespeare's play, Banquo cannot be the accomplice, a role that instead passes to Macbeth's wife.
So fascinated was James I in the notion of what makes a good king that he himself had written (in 1599) a handbook on good government, the Basilikon Doron. Some of these ideas of good kingship are listed by Malcolm as "the king-becoming graces" in Act IV, Scene 3 of Macbeth: "Justice, Verity, Temp'rance, Stableness, Bounty, Perseverance, Mercy, Lowliness, Devotion, Patience, Courage, Fortitude." Macbeth lacks all these kingly virtues, but his greatest vice is his impulse to lie — even to his own conscience — in his pursuit of power.
