Vikings plagued the coasts of Ireland and Britain in the 790s AD. Over time, their raids became more intense and by the mid 9th century, Vikings had established a number of settlements in Ireland and Britain and had become heavily involved with local politics. A particularly successful Viking leader named varr campaigned on both sides of the Irish Sea in the 860s. His descendants dominated the major seaports of Ireland and challenged the power of kings in Britain during the late 9th and 10th centuries. In 1014, the battle of Clontarf marked a famous stage in the decline of Viking power in Ireland while the conquest of England in 1013 by the Danish king Sveinn Forkbeard marked a watershed in the history of Vikings in Britain. The descendants of varr continued to play a significant role in the history of Dublin and the Hebrides until the 12th century, but they did not threaten to overwhelm the major kingships of Britain or Ireland in this later period as they had done before. This book