On the death of Malcolm II, the House of Alpin failed in the male line. Malcolm had two daughters, and the only surviving descendant of his cousin and immediate predecessor Kenneth III was a grand-daughter. King Malcolm's grandsons and King Kenneth's grand-daughter were the leading characters in the drama with which the history of the new dynasty opened.

Malcolm's elder daughter Bethoc married Crinan "the Thane", lay abbot of Dunkeld. At this period, when Celtic monasticism was in decline, lay abbots appear to have been as accepted a part of the ecclesiastical structure as they became centuries later on the eve of the Reformation. Crinan was a great nobleman, as his title implies, and he possessed the added prestige of belonging to the kindred of St. Columba. It was from his abbacy of Dunkeld that the new royal House took its name, for Crinan and Bethoc were the parents of King Duncan I.

Malcolm's younger daughter, whose name may have been Donada, married Finlaech, Mormaer of Moray (Mormaer was a Celtic title which appears to have been the equivalent of Thane or Earl), and they were the parents of Macbeth, who was therefore Duncan's first cousin. His name was in fact 'Maelbeatha', though it would be somewhat pedantic to revert to it.

Macbeth married Kenneth III's grand-daughter Gruoch, the original of Shakespeare's Lady Macbeth. Gruoch had been previously married to Gillicomgan, Mormaer of Moray, a cousin of Macbeth's father Finlaech. By her first marriage she had a son named Lulach.

The events in which Duncan, Macbeth and Gruoch took part were different in emphasis and timing from the familiar events of Shakespeare's tragedy.

Duncan was quite young, probably about thirty-three, when he succeeded his grandfather. At the time of his death in 1040 his two sons, Malcolm and Donald Ban (or Donalbain), were small children.

Macbeth, who was slightly younger than his cousin the King, had, according to the rule of tanistry, an equally good claim to the throne by right of birth, though Duncan had apparently succeeded as their grandfather's chosen heir. In 1040 Macbeth asserted his claim by force of arms, slew Duncan in battle and made himself king.

There is no knowing whether Gruoch's influence played any part in these events. She and Macbeth had no children, but it is likely that as the years passed, she may have become anxious to see her son Lulach accepted as his stepfather's heir.

Duncan's Queen had been a kinswoman of Siward, the Danish Earl who governed northern England under Edward the Confessor. Upon Duncan's death his elder son Malcolm was sent for safety to Siward's Court at York, and subsequently went to the Court of the English king; the younger son Donald Ban was sent to the Western Isles, and then possibly to Ireland. The 'separated fortune' of the brothers, to which Shakespeare referred, was to lead to separate interests and ultimately to their bitter enmity.

Meanwhile, Macbeth consolidated his triumph by defeating and slaying Duncan's father, Crinan, in a battle at Dunkeld in 1045.

Bloodshed, if not murder, had made him king, but he ruled successfully for seventeen years. He was an outstanding benefactor of the Church, and his rule was strong enough to permit his making a pilgrimage to Rome in 1050, where it was recorded that he "scattered money among the poor like seed".

Macbeth appeared to be liberal and secure, but he had an enemy whom the years could only make more dangerous. In 1054 Malcolm, with the assistance of his kinsman Siward, invaded Scotland, defeated Macbeth at Scone and wrested Lothian and Cumbria from him. (The name Cumbria was now given to the whole area which had previously been the kingdom of Strathclyde.) Three years later Malcolm invaded again and completed his victory when he defeated and slew Macbeth at Lumphanan in Aberdeenshire, in 1057.

Malcolm still had Lulach to deal with. Lulach was called "the Simple", so possible it is permissible to see the influence of Gruoch behind his coronation at Scone immediately upon the death of his stepfather. But early the following year Malcolm slew him, it was said, "by strategy". At the end of Shakespeare's play Malcolm, on his way to his coronation at Scone, refers to Macbeth and his wife with pious horror as 'this dead butcher and his fiend-like Queen', but perhaps when Malcolm became King of Scots, his had were no less bloodstained than Macbeth's.