Harthacnut or Cnut I was a semi-legendary King of Denmark. Ragnarssona þáttr makes Harthacnut son of the semi-mythic viking chieftain Sigurd Snake-in-the-Eye, himself one of the sons of the legendary Ragnar Lodbrok. The saga in turn makes Harthacnut the father of the historical king, Gorm. It has been suggested he is to be identified with the Hardegon of Northmannia whose early-10th century conquest of Denmark was related by Adam of Bremen.