The Cathedral lies within the precinct of Durham Castle, first constructed in the late eleventh century under the orders of William the Conqueror. Criterion (ii): Durham Cathedral is the largest and most perfect monument of ‘Norman’ style architecture in England. Durham Cathedral is a thriving religious institution with strong links to its surrounding community. A series of additions, reconstructions, embellishments, as well as restorations from the 11th century onward have not substantially altered the Norman structure of Durham Cathedral. Both the Castle and Cathedral are protected by designation with the Cathedral Grade 1 listed and also protected through the ecclesiastical protection system, and the Castle Grade 1 listed.