Ruins of Dormitory of Former Priory of St Mary

The ruins of the dormitory, or dorter, of the former Priory of St Mary date from the mid or late 13th century. Constructed from large blocks of red sandstone with ashlar dressings, this former two-storey building extended in a north-south direction from the south transept of the Cathedral and connected to the Fratry at right angles, forming the east range of the Cloisters.

Part of the west wall remains at ground floor level and features a pointed-arched doorway with a trumeau, which provided access through the undercroft to a vestibule for the Chapter House opposite. The east wall has mostly disappeared, with only the pointed-arched doorway into the Chapter House still visible. Inside the west wall, the springers for the rib vaulting of the undercroft can be seen, continuing along the east wall of the Fratry, with an additional springer on the inside of the east wall. Inside the Chapter House, adjacent to the Chapter House doorway, the beginning of the ribbed blind arching is present.

Excavations conducted in the 1950s uncovered the ground level, which was one metre below the current surface, revealing medieval tiles that were in place in the Chapter House but have since been removed. The slype arches that linked the wall to the Cathedral to the north were taken down in 1809 as part of the Cathedral grounds' new layout. Proposals from 1693 to convert the ruins into the Cathedral Library have been documented. Engravings from drawings by Thomas Hearne in 1777 and Robert Carlyle around 1791 depict the ground floor intact and are housed in Carlisle Museum.