We may regard the arches and lower stages of the central tower as the oldest part now remaining in its original condition. No doubt the Norman choir was the first to be built, as we find that it was almost the universal custom to begin churches at the eastern end, and gradually to extend the building westward, as funds and time allowed. Here, however, as in many other cases, the small Norman choir eastward of the central tower in course of time was considered too small, and the eastern termination had to be demolished to admit of the desired extension to the east. Norman choirs, as a rule, had an apsidal termination to the east, and it was not till Early English times that square east ends, which were characteristic of the English church in pre-Norman times, prevailed again over the Norman custom; and it is worthy of notice that this rectangular termination towards the east end remains a marked characteristic of the thirteenth-century work in England, Continental church-builders having retained the apsidal termination till the Renaissance. The side walls of the Norman choir extended two bays to the east of the central tower, and the nave four bays westward of the same. The transepts were shorter than at present, and the side aisles of the nave narrower. There appear to have been two side chapels to the choir, extending as far as the first bay eastward; beyond this to the east were two Norman windows on each side: these windows, parts of which remain, cut off by the Early English arches, were round-headed, and richly ornamented with chevron mouldings. They were uncovered at the time of the restoration, but are now again hidden by plaster. At the south end of the south transept a low building seems to have existed: the walls of this were raised when the south transept was lengthened in the fourteenth century. The Norman masonry may be seen under the south window of the transept, and a Norman string course runs round the sides and ends of the present transept. The aisles of the nave were not only narrower, but were also lower, than those now existing. It is also probable that these aisles did not originally extend as far westward as the nave. The windows of the Norman clerestory, which may still be seen from the interior, though all similar in design, are not alike in workmanship. The one over the narrow eastern bay on either side differs from those over the three bays farther to the west. Moreover, a continuous foundation has been discovered underneath the three western arches of the Norman nave. Possibly there was at one time a solid wall in this position, intended, however, from the first only to be temporary, and this was removed when the aisles, still in Norman times, were lengthened. The tower itself was not all built at the same time; the upper stages are ornamented with an arcading of intersecting arches indicating a somewhat later date.