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.
Olaf Guthfrithson Olaf Guthfrithson (Old Norse: "Óláfr Guðrøðsson" ; ; Old Irish: "Amlaíb mac Gofraid" ; died 941) was a Viking leader who ruled Dublin and Viking Northumbria in the 10th century. He was the son of Gofraid ua Ímair and great-grandson of Ímar, making him one of the Uí Ímair. Olaf succeeded his father as King of Dublin in 934 and succeeded in establishing dominance over the Vikings of Limerick when he captured their king, Amlaíb Cenncairech, in 937. That same year he allied with Constantine II of Scotland in an attempt to reclaim the Kingdom of Northumbria which his father had ruled briefly in 927. The forces of Olaf and Constantine were defeated by the English led by Æthelstan at the Battle of Brunanburh.