Diocese of Durham
When William the Conqueror became king of England in 1066, he soon realised the need to control Northumbria to protect his kingdom from Scottish incursions.After another rebellion, Waltheof was executed in 1075 and in his place Walcher was appointed earl, becoming the first bishop to exercise secular authority over the area.The lands between the Tyne and Tees, ruled by the bishops, became known as the 'County Palatine of Durham', a defensive buffer zone between England and the Northumbria-Scottish borderland.[2] Due to its strategic importance and its remoteness from London, the county palatine became a virtually autonomous entity, in which the bishop possessed the powers of a king.After the Union of the crowns of England and Scotland in 1603, the County Palatinate, founded to check Scottish incursions, increasingly became an anachronism.[3] In 1844 the Islandshire exclave was transferred to the jurisdiction of Northumberland, while the Bishop's duty to maintain a major fortress overlooking the Tweed at Norham also came to an end.1882 saw the Bishop lose the religious leadership for the whole of Northumbria when the part north of the River Tyne became the newly created Diocese of Newcastle.They also had a large round seal showing them seated administering justice on one side, and, on the other, armed and mounted on horseback.