Shakespeare drew the materials for the plot of Macbeth from Holinshed's Chronicles of Englande, Scotlande, and Ireland, the first edition of which was issued in 1577, and the second (which was doubtless the one the poet used) in 1586-87. The extracts from Holinshed in the notes will show that the main incidents are taken from his account of two separate events--the murder of Duncan by Macbeth, and that of King Duffe, the great-grandfather of Lady Macbeth, by Donwald. It will be seen, too, that Shakespeare has deviated in other respects from the chronicle, especially in the character of Banquo.
Although, as Knight remarks, "the interest of Macbeth is not an historical interest," so that it matters little whether the action is true or has been related as true, I may add, for the benefit of my younger readers, that the story of the drama is almost wholly apocryphal. The more authentic history is thus summarized by Sir Walter Scott:
"Duncan, by his mother Beatrice a grandson of Malcolm II, succeeded to the throne on his grandfather's death, in 1033: he reigned only six years. Macbeth, his near relation, also a grandchild of Malcolm II, though by the mother's side, was stirred up by ambition to contest the throne with the possessor. The Lady of Macbeth also, whose real name was Graoch, had deadly injuries to avenge on the reigning prince. She was the granddaughter of Kenneth IV, killed 1003, fighting against Malcolm II, and other causes for revenge animated the mind of her who has been since painted as the sternest of women. The old annalists add some instigations of a supernatural kind to the influence of a vindictive woman over an ambitious husband. Three women, of more than human stature and beauty, appeared to Macbeth in a dream or vision, and hailed him successively by the titles of Thane of Cromarty, Thane of Moray, which the king afterwards bestowed on him, and finally by that of King of Scots; this dream, it is said, inspired him with the seductive hopes so well expressed in the drama.
"Macbeth broke no law of hospitality in his attempt on Duncan's life. He attacked and slew the king at a place called Bothgowan, or the Smith's House, near Elgin, in 1039, and not, as has been supposed, in his own castle of Inverness. The act was bloody, as was the complexion of the times; but, in very truth, the claim of Macbeth to the throne, according to the rule of Scottish succession, was better than that of Duncan. As a king, the tyrant so much exclaimed against was, in reality, a firm, just, and equitable prince. Apprehensions of danger from a party which Malcolm, the eldest son of the slaughtered Duncan, had set on foot in Northumberland, and still maintained in Scotland, seem, in process of time, to have soured the temper of Macbeth, and rendered him formidable to his nobility. Against Macduff, in particular, the powerful Maormor of Fife, he had uttered some threats which occasioned that chief to fly from the court of Scotland. Urged by this new counsellor, Siward, the Danish Earl of Northumberland, invaded Scotland in the year 1054, displaying his banner in behalf of the banished Malcolm. Macbeth engaged the foe in the neighbourhood of his celebrated castle of Dunsinane. He was defeated, but escaped from the battle, and was slain at Lumphanan in 1056."
Whether Shakespeare was ever in Scotland is a question that has been much discussed. Knight (Biography, ed. 1865, p. 420 fol.) endeavours to prove that the poet visited the country in 1589, but most of the editors agree that there is no satisfactory evidence of his having ever been there.