OLAF or ANLAF (d. 981), king of the Danish kingdoms of Northumbria and of Dublin, was a son of Sitric, king of Deira, and was related to the English king Aethelstan. He was of Norse descent, and he married a daughter of Constantine II., king of the Scots. When Sitric died about 927 Aethelstan annexed Deira, and Olaf took refuge in Scotland and in Ireland until 937, when he was one of the leaders of the formidable league of princes which was destroyed by Aethelstan at the famous battle of Brun anburh. Again he sought a home among his kinsfolk in Ireland, but just after Aethelstan's death in 940 he or Olaf Godfreyson was recalled to England by the Northumbrians. Both crossed over, and in 941 the new English king, Edmund, gave up Deira to the former. The peace between the English and the Danes did not, however, last long. Wulfstan, archbishop of York, sided with Olaf ; but in 944 this king was driven from Northumbria by Edmund, crossing to Ireland he ruled over the Danish king dom of Dublin. From 949 to 952 he was again king of Northum bria, until he was expelled once more and he passed the remainder of his active life in warfare in Ireland. But in 980 his dominion
was shattered by the defeat of the Danes at the battle of Tara. He went to Iona, where he died probably in 981, although one account says he was in Dublin in 994. This however, is unlikely. In the sagas he is known as Olaf the Red.
This Olaf must not be confused with his kinsman and ally, OLAF (d. 941), also king of Northumbria and of Dublin, who was a son of Godfrey, king of Dublin. The latter Olaf became king of Dublin in 934; but he was in England in 937, as he took part in the fight at Brunanburh. After this event he returned to Ireland, but he appears to have acted for a very short time as joint king of Northumbria with Olaf Sitricsson. It is possible that he was the "Olaf of Ireland" who was called by the Northum brians after Aethelstan's death, but both the Olafs appear to have accepted the invitation. He was killed in 941 at Tyningham near Dunbar.
See W. F. Skene, Celtic Scotland (1876) ; J. R. Green, The Conquest of England (1899).