His next step was to remove the Norman apse and to build an aisled retro-choir of two bays. This is the architectural gem of the cathedral. The idea of it probably came from Hereford, where the retro-choir is a few years earlier. At Hereford, however, the retro-choir projects picturesquely, and forms an eastern transept. The central piers of the Chichester retro-choir are remarkably beautiful. They consist of a central column surrounded by four shafts very widely detached; column and shafts are of Purbeck marble. The capitals are Corinthianesque; their height is proportioned to the diameters of the column and shafts. This beautiful capital was reproduced a few years later by St. Hugh at Lincoln, and the pier at Boxgrove. The triforium is of quite exceptional beauty, as indeed is the whole design. Semicircular arches occur in the pier-arcade and triforium, and some of the abaci are square; otherwise the design is pure Gothic. Here, as at Abbey Dore, St. Thomas’, Portsmouth, Boxgrove, and Wells, we see the transition from the Transition to the “pure and undefiled Gothic” of St. Hugh’s choir at Lincoln. In these beautiful churches the ancient Romanesque style breathed its last. The aisles of the new retro-choir were continued on either side of the first bay of the Norman Lady chapel, whose three bays had probably been remodelled before the fire in Transitional fashion. The capitals of the Lady chapel are of exceptional interest and importance, as showing experimental foliation which had not yet settled down into the conventional leafage of early Gothic. The apse also of the south transept was replaced by a square chapel; and that of the north transept by a double chapel, now used as a library, in the vaulting of which the Norman zigzag occurs. III. A little later in the LANCET period was built (1199-1245) the lovely south porch, with small, exquisite mouldings, and charming foliated capitals and corbels. The difference between early Transitional, late Transitional, and Lancet foliation may be well seen by examining successively the capitals of the Lady chapel, the triforium of the retro-choir, and the south porch. The north porch is almost equally fine. The vaulting-ribs, square in section, show that the two porches both belong to the very first years of the thirteenth century. Rather later, the sacristy was built on to the south porch, with a massive vault supported by foliated corbels. IV. In the EARLY GEOMETRICAL period (1245-1280) building still went on unremittently. The south-west tower was raised to its present height; the low Norman central tower was replaced by a higher one: it is curious that this tower is oblong on plan; the transept, contrary to custom, being wider than nave or choir. A pretty circular window, with cusped circles and tooth ornament, was inserted in the eastern gable of the retro-choir, and a fine Galilee porch was added to the west front, as at Ely.