In the late 9th and early 10th Centuries the Danes and the Norsemen arrived taking without any major opposition whatever they wanted especially the rich and easy pickings of the Monasteries.
Although warriors, they did build fortified towns in which trade flourished.
However they continuously fought over land. In the North continuous fighting took place between York a strong Viking settlement and Bamburgh which remained the seat of the King of Northumbria who was still Saxon.
The coming of the next set of visitors was soon to settle such feuds.