Duncan I / Donnchad mac Crínáin (died 1040)
MacBeth / Mac Bethad mac Findlaích (died 1057)
Lulach mac Gille Coemgáin (died 1358)

Duncan was known as An t-Ilgarach, "the Diseased" or "the Sick", Duncan was son of Crínán, hereditary lay abbot of Dunkeld, and BethÓc, daughter of king Malcolm II of Scotland (Máel Coluim mac Cináeda).

Unlike the "King Duncan" of Shakespeare's Macbeth, the historical Duncan appears to have been a young man. He followed his grandfather Malcolm as king after the latter's death on 25 November 1034, without apparent opposition. He may have been Malcolm's acknowledged successor or tánaise as the succession appears to have been uneventful. Earlier histories, following John of Fordun, supposed that Duncan had been king of Strathclyde in his grandfather's lifetime, ruling the former Kingdom of Strathclyde as an appanage. Modern historians discount this idea.

Another claim by Fordun, that Duncan married the sister, daughter or cousin of Sigurd the Dane, Earl of Northumbria, appears to be equally unreliable. An earlier source, a variant of the Chronicle of the Kings of Alba (CK-I), gives Duncan's wife the Gaelic name Suthen. Whatever his wife's name may have been, Duncan had at least two sons. The eldest, Malcolm III (Máel Coluim mac Donnchada) was king from 1057 to 1093, the second Donald III (Domnall Bán, or "Donalbane") was king afterwards. Máel Muire, Earl of Atholl is a possible third son of Duncan, although this is uncertain.

The early period of Duncan's reign was apparently uneventful, perhaps a consequence of his youth. Macbeth (Mac Bethad mac Findláich) is recorded as his dux, literally duke, but in the context — "dukes of Francia" had half a century before replaced the Carolingian kings of the Franks and in England the over-mighty Godwin of Wessex was called a dux — this suggests that Macbeth was the power behind the throne.

In 1039, Duncan led a large Scots army south to besiege Durham, but the expedition ended in disaster. Duncan survived, but the following year he led an army north into Moray, traditionally seen as Macbeth's domain. There he was killed, at Pitgaveny near Elgin, by his own men led by Macbeth, probably on 14 August 1040.

He was succeeded by Mac Bethad mac Findlaích, anglicised as Macbeth, nicknamed Rí Deircc, "the Red King".

Macbeth was the son of Findláech mac Ruaidrí, Mormaer of Moray. His mother is supposed to have been a daughter of the Scottish king Malcolm II (Máel Coluim mac Cináeda).

He married Gruoch, the widow of his uncle Gille Coemgain, and took their son, Lulach, as his stepson. Gruoch was the granddaughter of Kenneth III.

On Duncan's death, Macbeth became king. No resistance is known at this time, but it would be entirely normal if his reign were not universally accepted. In 1045, Duncan's father Crínán of Dunkeld was killed in a battle between two Scottish armies.

John of Fordun wrote that Duncan's wife fled Scotland, taking her children, including the future kings Malcolm III (Máel Coluim mac Donnchada) and Donald III (Domnall Bán mac Donnchada, or Donalbane) with her.

After the defeat of Crínán, Macbeth was evidently unchallenged. Marianus Scotus tells how the king made a pilgrimage to Rome in 1050, where, Marianus says, he gave money to the poor as if it were seed.

In 1052, Macbeth was involved indirectly in the strife in the Kingdom of England between Godwin, Earl of Wessex and Edward the Confessor when he received a number of Norman exiles from England in his court, perhaps becoming the first king of Scots to introduce feudalism to Scotland. In 1054, Edward's Earl of Northumbria, Siward, led a very large invasion of Scotland. The campaign led to a bloody battle in which the Annals of Ulster report 3,000 Scots and 1,500 English dead, which can be taken as meaning very many on both sides, and one of Siward's sons and a son-in-law were among the dead.

Macbeth certainly survived the English invasion, for he was defeated and mortally wounded or killed by the future Malcolm III on the north side of the Mounth in 1057, after retreating with his men over the Cairnamounth Pass to take his last stand at the battle at Lumphanan. The Prophecy of Berchán has it that he was wounded and died at Scone, sixty miles to the south, some days later. Macbeth's stepson Lulach mac Gille Coemgáin was installed as king soon after.

Unlike later writers, no near contemporary source remarks on Macbeth as a tyrant. The Duan Albanach, which survives in a form dating to the reign of Malcolm III calls him "Mac Bethad the renowned". The Prophecy of Berchán, a verse history which purports to be a prophecy, describes him as "the generous king of Fortriu", and says:
The red, tall, golden-haired one, he will be pleasant to me among them; Scotland will be brimful west and east during the reign of the furious red one.

He was succeeded by his stepson, Lulach mac Gille Coemgáin, known in English simply as Lulach, and nicknamed Tairbith, "the Unfortunate" and Fatuus, "the Simple-minded" or "the Foolish. He was King of Scots between 15 August 1057 and 17 March 1058.

He appears to have been a weak king, as his nicknames suggest. He does, however, have the distinction of being the first king of Scotland of whom there are coronation details available. He was crowned in August 1057 at Scone.

Lulach was the son of Gruoch of Scotland, from her first marriage to Gille Coemgáin, Mormaer of Moray. Following the death in battle of Macbeth in 1057, the king's followers placed Lulach in the throne. Lulach ruled only for a few months before being assassinated and succeeded by Malcolm III (Máel Coluim mac Donnchada).

Lulach's son Máel Snechtai was Mormaer of Moray, while Óengus of Moray was the son of Lulach's daughter.

He is believed to be buried on Saint Columba's Holy Island of Iona in or around the monastery. The exact position of his grave is unknown.