From the battle of Maldon in 991 during the reign of Æethelred (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 and the long reign of his son, Cnut. This analysis of the invasions demonstrates beyond doubt that Æthelred 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. It is equally apparent that Swein was more than a marauding Viking adventurer: he was a sophisticated politician who laid the foundations for a great northern empire which was ruled by his descendents for many years after his death. New insight into this exciting period of English history is gained by focusing on the activities of Swein Forkbeard and, after his death in 1014, the Danish warlord Thorkell the Tall, both outstanding warriors and political leaders of what is sometimes called 'the Second Viking Age'. Many factors leading to the invasions and conquest are investigated through a critical analysis of the chronology of events, an explanation of the economic background, plotting the itineraries of the Scandinavian armies, and a fresh examination of the sources, including the 'Anglo-Saxon Chronicle', the 'Encomium', and 'John of Worcester's Chronicle'. IAN HOWARD has a PhD from Manchester University and is a Fellow of the Institute of Chartered Accountants in England and Wales. After a career in industry and commerce, he has returned to full-time research and has produced several papers covering a variety of aspects of early medieval history.