Early in the thirteenth century, _c._ 1220, the central tower collapsed, as at Winchester, Ely, Lincoln, etc. It fell towards the east, and seems to have broken down the arches of the presbytery. The Transitional piers were retained, more or less altered; but new pointed arches were built, and lancet windows were inserted in the new clerestory and east wall. In the aisles may be seen the low shafts of a Norman vault, and the corbels of a higher Lancet vault; it is uncertain whether either was ever executed. To this period belongs the very remarkable shrine of St. David: a very plain structure, designed for use—for very strange uses. Down below in each side are three openings, allowing three sick people at a time to lie beneath. (Perhaps they lay there all night, waiting for the Saint to come and touch them, as was the case in some shrines of Pagan Greece.) On the side next to the aisle are two large and shallow upright openings, and three small circular openings—the latter, perhaps, as in St. Alban’s shrine, to allow the patient to insert a diseased arm. A parallel to the lower openings may be found in the remains of the shrine now inserted under the effigy of Lord Stourton at Salisbury. When the restoration of the choir was completed (_c._ 1248), the next task seems to have been to build a processional aisle. The eastern walk of this was built fifteen feet east of the eastern wall of the cathedral, thus leaving a little open courtyard between the back of the east wall and the east walk of the new processional aisle. In the east wall there was a lower range of three tall lancets, which gave much light to the high altar beneath them. The authorities may then have left the little open courtyard to preserve the light of these three windows. But at Winchester and elsewhere the lower lights were sacrificed without demur; and the space between the east wall of the presbytery and the processional aisle, instead of being wasted, was utilised as a saint’s chapel or feretory, where—in the most honoured position in the church, close to the high altar—the shrine of the patron saint of the church was placed: shrines of St. Swithun and St. Birinus at Winchester, that of St. Werburgh at Chester, of St. Ethelreda at Ely, of St. Wulfstan at Worcester, of St. Cuthbert at Durham, of St. Chad at Lichfield. Now the shrine of St. David is artistically rude and uncouth, and occupies a by no means specially honourable position. May one conjecture that the original intention was to open arches in the east wall of the presbytery, and to build a new shrine for St. David, placing it above and behind the high altar, where it would be conspicuous to the very farthest end of the nave,—and that Welsh conservatism refused either to have a new shrine or to change the position of the old one? Before commencing the south walk of the processional aisle, the Lady chapel was erected (1290-1328). Its buttresses are late Gothic.