The surname MacBeth was first found in the Isle of Islay, where legend has it that the progenitor of this Clan is none other than Macbeth (Mac Bethad mac Findláich) (1005-1057), the High Steward of Moray. As his mother was a daughter of King Kenneth III, and he married Grudoch, a daughter of the son of King Kenneth III, he had as much of a claim to the Scottish throne as King Duncan I. MacBeth, therefore, challenged Duncan and defeated him in battle in 1040, assuming the throne.
Known in English simply as Macbeth, he was last Celtic king of Scotland, ruling from 1040 to 1057, when he died in battle against future king Malcolm of the Canmore dynasty.
He is best known through the Shakespearean drama bearing his name. Thespians rarely mention the play by the name and typically call it "the Scottish play" as they believe that by uttering the name brings one bad luck.