Danelaw

The Danelaw was the part of England settled and ruled by Scandinavians in the late 9th and 10th centuries, north and east of a line roughly along Watling Street. It took shape after the Great Heathen Army settled Northumbria, East Anglia and eastern Mercia, and its boundary was set out in Alfred's treaty with Guthrum. West Saxon kings reconquered it in the 10th century, but Danish law and place names long survived there.