joined him there, and that it was he who in 940 plundered Kilcullen in Kildare. Meanwhile Æthelstan, shortly after his victory at Brunanhurh, had hiuided over Northumbria to Eric of the Bloody Axe, son of Harold Harfagr of Norway, to hold against the Danes (Hist. Reg. Olavi Tryggvii in Island, Script. Hist. l22). Soon after Æthelstan's death in 940, the Northumhrians threw off their allegiance to his successor, Eadmund, and called 'Olaf of Ireland' to be their king. Olaf Sitricson is porobably meant; but he was soon followea to England by Olaf Godfreyson, with whom he apparently shared the kingship until the latters death in 941. Olaf Sitricson went first to York, then, turning south, besieged Northampton and stormed Tamworth. Eadmund met him, probably near Lincoln, and, though the order of events is variously given, the archbishops Odo and Wulfstan appear at this point to have intervened and effected a compromise. By it all Deira north of Watling Street was ceded to the Danes. In 942 mund won back the five boroughs, Lincoln, Leicester, Stamford, Nottingham, and Derby; and this success has been connected with the death of Olaf Godfreyson shortly before. But in 942 Olaf Sitricson, who now shared the kingship with Reginald Godfreyson, obtained the powerful support of Archbishop Wulfstan of York, with whom he was besieged in Leicester by Eadmund in 943, and forced to flee by night. Again a treaty was made this year, but not, it is to be inferred, so favourable to the Danes. Both Olaf Sitricson and Reginald Godfreyson were received into Eadmund's friendship and into the Christian church.
Such a state of things was clearly abnormal, and in 944, when Eadmund had gone south into Wessex, Olaf and Reginald seized the opportunity to make a raid into the territory nom which they had been cut off. Eadmund returned, drove them from the country, and formally annexed Deira.
In the year of Olaf's expulsion from Northumbria, Dublin, the capital of the Irish dominions of his house, was sacked by the native Irish. Next year Olaf reappeared in Ireland, and either drove out Blacar Godfreyson, who had been left in command, or, entering into alliance with him, restored Dublin and firmly established his rule over the Irish dominions of his family. In the same year he allied himself with the bitter enemy of his race, Congalach, king of Ireland, against the Irish clan of the O'Cananain, and in 946 doubtless led the Dublin Danes in their attack upon the monastery of Clonmacnoise in Omdy. In 947 Olaif, still in alliance apparently with King Congalach, was severely defeated by Ruadhri O'Canannain at Slane in Meath, and lost many of his men. The alliance with King Congalach certainly terminated in this year; for Dublin was again plundered, and Blacar Godfreyson, who was in command on this occasion, was defeated and slain. It is possible that this was an attack made in Olaf's absence; for it was in 949 that he made his last attempt to regain his father's kingdom of Deira. He then succeeded in establishing his power for three years, till the Northumbrians, with their usual faithlessness, rose against him, and he was finally driven from the country in 952. Northumbria submitted to Edred, and after 954 was ruled by his earls.
In 953 Olaf was again in Ireland, and, in alliance with Toole, son of the king of Leinster, made plundering raids into the modern counties of Waterford and Wicklow. Three years later he took in ambush and slew his old enemy, King Congalach. In 962, with the Gaill of Dublin, he pursued, defeated, and drove back to his ships a certain Sitric Cam, possibly a Scottish chieftain, who had landed in Ireland, and penetrated as far as Kildare (Four Masters, ii. 683; but cf . Todd, War of the Qaedhily p. 286). Two years later Olaf met with a reverse at Inistioge in the modern county of Kilkenny, and lost many of his men, but had apparently sufficiently recovered in 970 to join the Leinstermen in the plunder of Kells, in what is now Meath, where he seized many hundred cows. He also gained a victory over one of the Irish clans near Navan in Meath. It was possibly in this same year (970) that he entered into a short-lived alliance with the son of the late King Congalach, and defeated the reigning king, Domhnall O'Neill, at Kilmoon, near Dunshaughlin in Meath. A few years later, probably in 977 or 978, Olaf slew the heir to the throne of Ireland of each of the two contending royal lines, those, namely, of the northern and southern O'Neill, and shortly after probably led the Dublin Danes to his last victory at Belan, near Athy in Kildare.
In 980 was fought the fatal battle of Tara, which broke the power of the Norse kingdom of Dublin. With the Dublin Danes were fighting their kinsmen from the islands. It is uncertain whether Olaf was himself present; but the battle was fiercely contested Dy his sons, 'and it was woe,' says the chronicler, 'to both sides.' The Danes were completely defeated, Olaf's heir, Reginald, and a great number of his chieftains slain. With them Olaf saw the power he had
