William the Conqueror did not instantly win over the whole of England in 1066. He needed help. His thorniest problem was the burly earldom of Northumbria. After learning the hard way that nobles could not be trusted, William I placed his faith in the Bishop of Durham instead. From 1075, the role became a Prince Bishop, giving the holder unprecedented secular powers to raise an army, mint coins and levy taxes. In the subsequent 750 years, 56 different Prince Bishops presided over County Durham, which was virtually an independent state, answering only to the king and God, and often negotiating on behalf of the monarch. But with such great power, comes great responsibility. Were the Prince Bishops inspiring or insidious leaders?
Auckland Castle, bursting with its little-known legacy, is finally…