Who was the half-brother of Sweyn Haakonsson that participated in the conquest of English by King Canute the Great?
Eiríkr Hákonarson Eric Haakonsson (960s – 1020s) was Earl of Lade, Governor of Norway and Earl of Northumbria. He was the son of Earl Hákon Sigurðarson and brother of the legendary Aud Haakonsdottir of Lade. He participated in the Battle of Hjörungavágr, the Battle of Svolder and the conquest of England by King Canute the Great.
Harthacnut I of Denmark Harthacnut or Cnut I (Danish: Hardeknud ) (born c. 880) 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.