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. Bishop Langton also erected the shrine of St. Chad at an expense of £2000. This shrine stood behind the high altar in the most eastern bay of the retro-choir, and, as was usual, had on its western side an altar dedicated to the saint. A similar arrangement can still be seen in Westminster Abbey, where the shrine of Edward the Confessor stands behind the reredos. The space behind the reredos, with the corresponding bays of the aisles, were in the past called the lady choir. This portion was separated from the rest of the choir by the reredos in the centre, and by screens in a line with the reredos in the aisles; there was a chapel in the lady choir at the end of each aisle, but to whom they were dedicated is doubtful. Stukeley, writing in 1715, says: "In St. Peter's Chapel, which is now a place to lay scaffolding and ladders, etc., was painted upon the wall St. Peter crucified with his head downwards, and two other apostles, etc. And in this place is the noted St. Chad's tomb, though defaced, removed from the lady choir to be put here since the Restoration." The same writer also tells us that: "Over across the middle of the said choir was a rood loft, finely carved and gilded, and St. Chad's shrine, but destroyed in time of war."