No historical document exists that can apply to the building of the nave; but that must have come next, and have been in progress almost before the north transept could have been finished. The west front was commenced somewhere about the beginning of the last quarter of the thirteenth century, and, including the two towers which form such an important part of it, must have taken a very long time to complete. From the thorough examination made when the recent restorations were in progress, it was decided that these towers were built in three distinct stages--the lowest, which just included the row of kings, being assigned to about 1280; the next stage to 1300; and the upper part, including the belfry windows, to about 1330, while the spires were not finished till some time after.
Walter de Langton became bishop in 1296, and of him it is distinctly recorded that he commenced the Lady Chapel. From an old register in the Salt Library at Stafford, it appears that Langton left £80, 13s. 3d. for the building of the chapel. He died in 1321. And, in 1323, there is another entry showing that the chapter came to some agreement with his executor by which each party should pay half the cost of finding a quarry for the stone; so that it does not appear that building operations had proceeded very far at his death. It is interesting to note, as the same source shows us, that the money left by the bishop was partly on loan to King Edward II. for the expenses of his wars with Scotland, which wars had ended so disastrously at Bannockburn. In the following reign, Edward III. was asked by the chapter to repay what was still owing of this money.
The Lady Chapel was probably erected beyond the eastern end of the church as it then stood; and while this was being done, the Early English presbytery was taken down and rebuilt in the Decorated style to match the new Lady Chapel, and the old clerestory of the choir was also rebuilt in the same style. The main idea was to obtain uniformity; but as it apparently was not proposed to take down the sacristy on the south, nor the chapter-house on the north, it was not considered necessary to pull down the choir--_i.e._ the last three western bays--any lower than the triforium; for the lower parts would be hidden by these buildings from the outside, and inside various shifts were resorted to to obtain uniformity. The work almost certainly grew from east to west gradually, as the clerestory of the choir end is lighter than that of the eastern or presbytery end; so that no doubt the pulling down of the old choir clerestory was only done after the building of the eastern end made it seem better to alter the rest into uniformity. With regard to the inside effect, Professor Willis says: "The front half of their pier arches (those belonging to the three western bays), however was removed and mouldings given them corresponding to those of the new presbytery. Their piers also were slightly altered, although partially concealed by the choir stalls. By these arrangements the aspect of the whole interior of the choir and presbytery was made uniform." How far this theory is sound will be seen when the alterations early in the present century are considered in their place.