Duncan did not possess political or military acumen. This made him unpopular with subjects and nobility. Killed by Macbeth on August 15, 1040,, he is chiefly remembered for Shakespeare's depiction.
The feud between these two might relate to a dispute over succession, but details are obscure. The only certainty is that MacBeth killed Duncan in battle near Elgin, Moray.
Donnchad "the Gracious" mac Crínáin, Rí na h'Alba; Donnchad mac Crínáin (Modern Gaelic: Donnchadh mac Crìonain) anglicised as Duncan I, and nicknamed An t-Ilgarach, "the Diseased" or "the Sick"
before 1034: ruled as rex Cumbrorum in the Kingdom of Strathclyde
1034-1040: King of Scots. succeeds maternal grandfather, Malcolm III. ... "first example of inheritance of the Scottish throne in the direct line", as opposed to previous tanistry system.
1038: attacked by Eadulf of Berncia;Ealdred, Earl of Northumbria, invaded Strathclyde, perhaps in an attempt to wrest it from the Scots.
1039/40: attacked Durham but defeated. Retreated to Moray, but twice defeated by Earl of Orkney's son, Thorfinn, before being killed in battle. He died at Bothnguane.
↑ Malcolm violated system of succession where kingship alternated between two branches of the royal family. Duncan succeeded peacefully, but soon faced rivalry of Macbeth, Mormaor (subking) of Moray, who probably had a better claim. Duncan sieged Durham unsuccessfully in 1039 and in the following year was murdered by Macbeth. Duncan's elder son later killed Macbeth and ruled as King Malcolm III Canmore (1058-93).
↑ p. unknown. She has been referred to in connection with Siward of Northumbria ... as a cousin, sister, or daughter. ... (Scottish Regnal List I calls his wife Suthen; John of Fordun calls her kinswoman of Siward Biornsson, Earl of Northumbria; UK's monarch history states she was Siward's cousin).
↑ 1040: Durham. Like his grandfather's attack in 1006, it ended in disaster, with Scottish forcesfleeing, and Scottish heads decorating the Durham marketplace. This defeat seems to hae weakened his authority so severely that Macbeth of the Cenel Loairn was able to defeat and kill him in battle near Elgin (Davidson 1995
Ashley, M. (2008). A Brief History of British Kings and Queens, (pp.106-107). Philadelphia, PA: Running Press Book Publishers. Print.
Gospatric Northumberland-35 mistakenly appeared as a son of Bethoc (no father) and is a faulty profile. Should not be a brother of Duncan, and should be merged Dunbar-27 to eliminate the bogus profile. unsourced and in error on parents, family
Note: Duncan's wife is Sybill or Suthen. Her parents are UNKNOWN but she is often said to be somehow related to Siward of Northumbria... either as a cousin, sister, or daughter. Please do not connect her with Siward.