Viking invasion of Britain
The settling of a large part of conquered England by the Danes became known as the Danelaw. It became the part of England where the laws and customs were Danish not English. At this point England became divided into three parts. These were Wessex, English Mercia and the Danelaw. The Danelaw was a mixture of the native populations and the members of the great army who settled there. Many placenames were Danish. Many of the words in the English vocabulary have Danish origins. As late as the 11th century when a Scandinavian came to England he did not feel out of place. The languages was the same and the customs were the same. This was true until the Norman conquest of England in 1066 when French was introduced into England.