Macbeth is the shortest of Shakespeare's tragedies, and scholars have surmised that the text may have been truncated, perhaps by Shakespeare himself. Yet its brevity is a virtue, for the play's concentrated tension contributes enormously to what may be the most horrific of Shakespeare's works. Other plays are as gory. In other plays, as many or more characters are murdered. But none of the others is so preoccupied with the concept of murder, with the deliberate planning and outcome of the act. Furthermore, the motivation for this series of murders is uncomfortably clear: so eager is Macbeth to possess and maintain power that he is willing to kill in cold blood.
The creation of the play may have been influenced by the new king of England, James I, formerly James VI of Scotland, who succeeded to the throne in 1603 upon the death of Elizabeth. He had a keen interest in demonology, and even wrote a book, Daemonologie ( 1597), which Shakespeare probably used in writing the scenes involving the witches. Furthermore, James had a deep concern for Scottish history, and could trace his ancestry back to the eleventh century, the time of the story. Shakespeare's main historical reference was Holinshed Chronicles of England, Scotland, and Ireland ( 1577), the primary source of his history plays. In his adaptation, however, the playwright made several deviations. In Holinshed, Macbeth has a legitimate grievance against a young and incompetent Duncan. In the play, Duncan is older and decent, and Macbeth's reason for murder is not political, but personal. Banquo, Macbeth's accomplice in Holinshed, is a noble bystander in Shakespeare's play, possibly because Banquo was said to be an ancestor of James. Finally, Shakespeare dispenses with what Holinshed described as a successful ten-year reign by Macbeth and turns him into a tyrant who rules briefly and cruelly. The impact of all these alterations is an emphasis not on political ramifications, as in Holinshed, but on psychological and moral implications.
One sidelight: Macbeth has long been regarded as a jinxed work, because so many productions have gone awry. Thus theatrical professionals often prefer that it not be spoken of by its title, but instead referred to as "the Scottish play."