Duncan I, and nicknamed "the Diseased" or "the Sick" was king of Scotland (Alba) from 1034 to 1040. He is the historical basis of the "King Duncan" in Shakespeare's play Macbeth.
Details of Duncan's marital life are a matter of debate among historians. The Scottish Regnal List I calls her Suthen, and John of Fordun calls her a kinswoman of Siward Biornsson, Earl of Northumbria. The United Kingdom's official History of the Monarchy states that she was Siward's cousin.