The east end is naturally the oldest part and most closely resembled its French original; the eight round columns of the apse have good plain capitals like those found in so many early Cistercian churches, even in Italy;[52] the round-headed clerestory windows are high and narrow, and there are well-developed flying buttresses. Unfortunately all else has been changed: in the apse itself everything up to the clerestory level has been hidden by two rows of classic columns and a huge reredos, and all the choir chapels have been filled with rococo woodwork and gilding, the work of an Englishman, William Elsden, who was employed to beautify the church in 1770.[53] Why except for the choir aisle, and the chapels in choir and transept, the whole church should be of the same height, it is difficult to say, for such a method of building was unknown in France and equally unknown in Spain or Portugal. Possibly by the time the nave was reached the Frenchmen who had planned the church were dead, and the native workmen, being quite unused to such a method of construction, for all the older vaulted churches have their central barrel upheld by the half-barrel vault of the galleries, could think of no other way of supporting the groining of the main aisle. They had of course the flying buttresses of the choir apse to guide them, but there the points of support come so much closer together, and the weight to be upheld is consequently so much less than could be the case in the nave, that they may well have thought that to copy them was too dangerous an experiment as well as being too foreign to their traditional manner of construction.[54] Whatever may be the reason, the west aisle of the transept and the side aisles of the nave rise to the full height of the building. Their arches are naturally very much stilted, and with the main vault rest on piers of quite unusual size and strength. The transverse arches are so large as almost to hide the diagonal ribs and to give the impression that the nave has, after all, a pointed barrel vault. The piers are throughout cross-shaped with a half-shaft on each cardinal face: at the crossing there is also a shaft in the angle, but elsewhere this shaft is replaced by a kind of corbel capital[55] at the very top which carries the diagonal ribs--another proof, as is the size of the transverse arches, that such a ribbed vault was still a half-understood novelty. The most peculiar point about nave piers is the way in which not only the front vaulting shafts but even that portion of the piers to which they are attached is, except in the two western bays, cut off at varying heights from the ground. In the six eastern bays, where the corbels are all at the same level, this was done to leave room for the monks' stalls,[56] but it is difficult to see why, in the case of the following five piers, against which, as at Clairvaux, stood the stalls of the lay brothers, the level of the corbels should vary so much.