William the Conqueror appointed William de St-Calais as Bishop of Durham in 1080 AD. County Durham was not featured in the Domesday Book of 1086 as the Bishop of Durham had exclusive tax rights over the area. | William the Conqueror appointed William de St-Calais as Bishop of Durham in 1080 AD. County Durham was not featured in the Domesday Book of 1086 as the Bishop of Durham had exclusive tax rights over the area. |