Retford has traditionally been placed within the Anglo-Saxon kingdom of Mercia because it is situated within Nottinghamshire. More recent historical research suggests that the South of Nottinghamshire and North Nottinghamshire may have had very different cultures. North Nottinghamshire, including Retford, belonged to an area called Bernet-seatte, which later became Bernesedelaue and then Bassetlaw. This territory is now thought to have been "substantially British". It practised, for example, partible inheritance, had British placenames and there is relatively little Anglo-Saxon material. West and East Markham seem to have been on the boundaries of this territory (maerc means boundary). It is not known if Bernet-seatte extended across the whole of North Nottinghamshire, or whether the Kingdom of Lindsey controlled the East of this area (Retford and Retford rural district). What is known is that this corridor of land was seen as strategic, which is why several notable battles were fought in the area between the kings of Northumbria and Mercia.