The County of Mortain was a medieval county in France centered on the town of
Mortain. A choice landholding, usually either kept within the family of the
duke of Normandy (or the
king of France) or granted to a noble in return for service and favor. This was the main reason Mortain had so many counts, as shown below, during its long history.
^There are apparently few certain facts about William Warlenc, who was deprived of the County to the benefit of Robert (sometimes said to have been c.1055).