Who was the half-brother of Sweyn Haakonsson that participated in the conquest of English by King Canute the Great?
Sweyn Haakonsson Sweyn Haakonsson (Old Norse: "Sveinn Hákonarson", Norwegian: "Svein Håkonsson" ) (died c. 1016) was an earl of the house of Hlaðir and co-ruler of Norway from 1000 to c. 1015. He was the son of earl Hákon Sigurðarson. He is first mentioned in connection with the battle of Hjörungavágr, where the "Heimskringla" says he commanded 60 ships. After the battle of Svolder in the year 1000, Sveinn became co-ruler of Norway with his half-brother, Eiríkr Hákonarson. After Eiríkr went to England in 1014, Sveinn was co-ruler with Hákon Eiríksson. In 1015, Óláfr Haraldsson arrived in Norway and claimed the throne. He defeated Sveinn and his allies in the battle of Nesjar. Sveinn retreated to Sweden, intending to muster a force to retake Norway but he died of an illness before he could return.
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.