For three centuries, beginning shortly before ad 800, the British Isles were subject to raids from Scandinavia. Initially these were hit-and-run affairs targeting vulnerable coastal sites, principally monasteries, such as Lindisfarne, Monkwearmouth and Iona. As the raiding parties gained in size and condence, and as the need for reward increased, they seized land as well, although the rate at which raiding turned to settlement varied from area to area. Norse colonies were founded in the Northern and Western Isles of Scotland and on the Isle of Man. Documentary sources for these regions are scarce, and we are reliant on archaeological evidence. For England, however, the Anglo-Saxon Chronicle provides a near-contemporary, if one-sided, account of raids, annexations and Scandinavian invasions. It records the presence of a highly mobile Danish ‘great army’ in England from ad 865. Having captured York in ad 866, this army seized territory in Northumbria, Mercia and East Anglia. Within these areas, which became known as the Danelaw, many Scandinavians settled.