Then came the great building-prelate of St. David’s, Bishop Gower (1328-1347). (1) He completed the processional aisle, building the whole of the south walk and completing the north walk. (2) Like Abbot Thokey, at Gloucester, he transformed the Norman south aisle of the nave into the style of his day (Curvilinear), and built a south porch. (3) East of the north transept he built a three-storied building, the lower part as a chapel to St. Thomas of Canterbury, the upper part as a chapter-house. (4) He raised the tower one stage above the roofs. (5) He raised the walls of the aisles, and inserted Curvilinear windows. (6) He separated the presbytery from the choir, which as at Gloucester is beneath the central tower, by a parclose screen—a very rare feature. (7) He built the wood throne of the bishop; it seems, however, to have been reconstructed in the fifteenth century. (8) He built for himself the magnificent palace, and another at Lamphey, besides Swansea castle and church. (9) His most beautiful work is the magnificent choir-screen, one of the grandest examples of mediæval art. It consists of three compartments of stone, surmounted by a coved cornice of wood. The southern compartment has two pointed arches, with compound cusping and rich crockets; and within, the tomb and effigy of the bishop. The central compartment is occupied by the doorway and vaulted vestibule leading from the nave to the choir; on either side of the vestibule are effigies of priests. The northern compartment seems to consist of thirteenth century arcading, which has been worked up to serve as a reredos to an altar. To the Perpendicular period belong the stalls, which have good misereres (1460-1480); the elaborate wooden roof of the nave (1472-1509) and that of the presbytery, which is a little earlier. Early in the Tudor period Bishop Vaughan (1509) added another story to the tower, and built himself a chapel in the empty space between the east wall of the presbytery and the east walk of the processional aisle, vaulting it with fan-tracery. Externally, the cathedral is simple and plain, in harmony with its bleak and wild surroundings. Internally, like Canterbury and Winchester, it gains dignity from the greater height of the choir. The whole floor of the nave slopes upwards from west to east, and the choir is elevated eight steps above the level of the nave. GLOSSARY. _Abacus_ The flat slab on the top of a capital. _Ambulatory_ The processional aisle at the back of the high altar. _Apse_ The eastern termination—semicircular or polygonal—of a choir or its aisles, or of a transept. _Arcade_ A series of arches. _Pier-arcade_ The piers and arches separating the side-aisles from the central aisle or nave. _Battlement_ A notched or indented parapet.