the warden and fellows of the collegiate church were translated into a dean and canons in preparation for becoming the cathedral of the new Diocese of Manchester which came into effect in 1847. Initial proposals for a new cathedral to be built to the designs of R.C. Carpenter on Piccadilly Gardens were not proceeded with. The building was extensively renovated in 1882. During the Manchester Blitz in 1940, a German bomb exploded a few yards from the north-east corner, severely damaging the cathedral roofs and demolishing the medieval lady chapel and James Stanley's chantry chapel. All stained-glass windows were blown out, the organ-case over the pulpitum was destroyed, and the medieval choir stalls toppled inwards so as to meet one another. It took almost 20 years to complete the repairs, in the course of which the Lady Chapel was rebuilt to the designs of Hubert Worthington and the St John the Baptist Chapel was refitted as the regimental chapel for the Manchester Regiment. The cathedral was again damaged in the IRA bombing in June 1996. The cathedral houses extensive parish and historical archives, dating back to 1421. In 2003, a project began to provide an exhaustive catalogue of the archive's contents to the public. The cathedral was granted Grade I listed building status in January 1952. Grade I structures are considered to be "buildings of exceptional interest". Architecture The cathedral is constructed of three types of stone. The walls and internal piers were originally constructed in a dark purple-brown Collyhurst sandstone formed in the Early Permian period. This is now visible only in the tower arch of the nave, in the interior of the Jesus Chapel and in the chancel; as in the early 19th century all the surfaces of the nave and aisles were scored to be encased in Roman Cement. This damaged the structure so severely that most internal and external stonework had to be replaced in the later 19th century restorations in buff-grey Fletcher Bank Grit from Ramsbottom. The nave floors have, since the 1960s, been relaid in limestone from the Peak District which contains crinoid fossils. Restorations By the 1840s the external and internal stonework was in a poor state, partly due to the poor weathering qualities of the Collyhurst sandstone, but also because of an ill-advised attempt to lighten the interior by coating the internal surfaces of the nave with Roman cement by John Palmer.