King Duncan I was a historical figure who ruled as the King of Scotland from 1034 until his death in 1040. He was a member of the House of Dunkeld and is often remembered for his efforts to consolidate power and maintain peace in his kingdom. His reign was marked by conflicts with rival factions, including the Macbeth clan. Duncan's rule came to an end when he was killed by Macbeth, who was a nobleman and his cousin. This event is famously dramatized in William Shakespeare's play "Macbeth," which portrays Duncan as a virtuous and benevolent ruler, contrasting with the ambition and treachery of Macbeth.