The gradual acquisition of powers by the bishops led to Durham being recognised as a palatinate by the late thirteenth century, one of several such counties in England during the Middle Ages.

[3] The origins of the Liberty trace back to the year 684, when King Ecgfrith of Northumbria bestowed a significant territory upon St. Cuthbert, following the latter's election as the Bishop of Lindisfarne.

This territorial expansion began under the leadership of Bishop Ecgred, who acquired two substantial blocks in the south-east and south-west regions of the designated area between 830 and 845.

[8] With the possible exception of the Wapentake of Sadberge, the area north of the Tees lay outside of the West Saxon administrative system of shires and hundreds/wapentakes.

[6][11] When William the Conqueror became the king of England in 1066, he quickly realized the need to control Northumbria to protect his kingdom from Scottish invasion.

In 1075, shortly after the Norman conquest, William the Conqueror allowed Bishop Walcher to purchase the earldom of Northumbria after its previous holder, Waltheof, rebelled against the king.

[11] Following the Norman invasion, the shire system was extended north of the Tees and the county of Northumberland was formed, encompassing the lands of the Earldom of Bamburgh, the Liberty of Durham and Wapentake of Sadberge.

[15] These arguments appear to have been accepted, as by the 14th century Durham was considered a County Palatine which received royal mandates direct.

[16] The later history of the palatinate is characterised by the Crown and parliament slowly diminishing the powers of the bishops and incorporating the county into the regular system of local government in England.

[12] In March 1553 the diocese was briefly abolished; the bishop, Cuthbert Tunstall, had been removed from office and imprisoned in 1552 because he did not support the religious policies of Edward VI's de facto regent, John Dudley.

[23] At its greatest extent, the county palatine consisted of a large, contiguous territory around Durham and several exclaves to the north and south.

[29][30] Durham itself was divided by the 13th century into four "wards" (equivalent to hundreds) named after their chief towns: Chester-le-Street, Darlington, Easington and Stockton.

[31] There is no evidence that the bishops paid danegeld, which was first collected in 991; after the Norman Conquest it became a regular tax based on the Domesday survey, which Durham was also omitted from.

[40][41][42] During the vacancy which followed the death of bishop Philip of Poitou in 1208 King John appears to have raised money in the palatinate, but this was regarded as an infringement of local privilege.

During the medieval period, St Cuthbert became politically important in defining the identity of the people living in the semi-autonomous region.

The inhabitants of the Palatinate became known as the "haliwerfolc", an Old English phrase which roughly translates as "people of the saint", and Cuthbert gained a reputation as being fiercely protective of his domain.

"[47] Symeon of Durham related a tale of a tax gatherer named Ranulf, who was sent by William the Conqueror to force the people of the saint to contribute to the national revenue.