Viking Invasion of Northumbria

When King Edward the Confessor died on January 5th 1066, he did not leave behind a direct heir. This left a serious power struggle in the Anglo-Saxon kingdom but it was temporarily remedied with the establishment of Harold of Wessex as high king. Harold of Wessex was, by default, the rightful heir to the throne but Tostig Godwinson, Harold's bitter brother, had not taken favorably to the position. Being an unfair and terrible leader, Tostig fed the very same rebellion that would have him kicked out his governing position in Yorkshire a year earlier. The rebels demanded that someone else be placed as their governor but they also demanded that Tostig be kicked out of the kingdom completely. Edward the Confessor sent his son, Earl Harold, to negotiate with the rebels and he complied with their demands for the sake of having peace and loyalty in the province of Yorkshire. Exiled and humiliated, Tostig plotted vengeance. After an unsuccessful attempt at forming an allegiance with Duke William of Normandy, Tostig managed to convince the prestigious viking king Harald Hardrada of Norway to take the throne from right under Harold. While Tostig met in battle with the troops positioned at York, Harald met the royal army led by Harold. Despite having much more combat experienced men, Harald's 9,000 men could not stand a chance against the 15,000 that marched for the crown but they still fought bravely. There is even a story about a big warrior holding his own against the entire English force on a narrow bridge before he was overwhelmed and killed but not before taking 40 men with him. This delayed the English and gave the vikings time to reorganize their shield wall and brace for battle. The battle raged on all day long up until the point where Harald was hit by an arrow and killed. The leader of Norway now lay dead on English soil and his men tired. Tostig tried to rally the few men that remained but failed in his attempt and he proceeded to die in battle. The vikings fled with less ships that they arrived with. 

The battle at Stamford Bridge marked the last viking invasion of Northumbria.

Sources:
http://www.battlefieldstrust.com/resource-centre/viking/battleview.asp?BattleFieldId=41
http://www.britainexpress.com/History/battles/stamford-bridge.htm
http://www.historic-uk.com/HistoryMagazine/DestinationsUK/The-Battle-of-Stamford-Bridge/