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Olaf Guthfrithson(ō`läf gŭth`frĭth'sən), d. 941, Norse king of Dublin (934–41). His father, Guthfrith, king of Dublin and of York, had been driven out of England by AthelstanAthelstan
, d. 939, king of Wessex (924–39), son and successor of Edward the Elder. After coming to the throne, he vigorously built up his kingdom on the foundations established by his grandfather Alfred.
..... Click the link for more information. in 927. Olaf led (937) his allies, Constantine of Scotland and Owen of Strathclyde, against Athelstan in the battle of Brunanburh and was severely defeated. He returned to Ireland, but after Athelstan's death he invaded (939) York. A treaty between Olaf and King EdmundEdmund,
921–46, king of Wessex (939–46), half-brother and successor of Athelstan. Immediately after his accession he had to face an invasion of Irish vikings led by Olaf Guthfrithson.
..... Click the link for more information. , successor of Athelstan, gave Olaf control over Northumbria and part of Mercia. His successor, Olaf Sihtricson (sĭt`rĭk'sən), d. 981, often called Olaf Cuaran, was expelled from Northumbria by Edmund in 944. He returned to rule in Ireland, where he was in 980 defeated at the battle of Tara. He died a penitent at the monastery of Iona.