From the battle of Maldon in 991 during the reign of ?ethelred (the Unready), England was invaded by Scandinavian armies of increasing size and ferocity. Swein Forkbeard, king of Denmark, played a significant part in these invasions, which culminated in the domination of England the long reign of his son, Cnut. This analysis of the invasions demonstrates beyond doubt that ?thelred was no indolent and worthless king who bribed invading Vikings to go away: his relationship with the Scandinavian armies was more complex and more interesting than has been supposed.