It has been mentioned above that Sir William Preston of Gorton was a benefactor of St. Giles’. In 1454, after much trouble and expense abroad, and aided by “a high and mighty prince, the King of France, and many other Lords of France,” he succeeded in obtaining an arm bone of the Patron Saint, which he generously bequeathed to the church. The Town Council were so gratified with the gift that they resolved to add an aisle to the choir in commemoration of the event, and to place therein a tablet of brass narrating the bounty of Sir William. This aisle was to be built within six or seven years, “furth frae our Lady Isle where the said William lyis.” From this it appears that the south aisle of the nave was known as the lady chapel, and that Sir William had been buried there. The above resolution was carried into effect, and a new aisle, called the Preston Aisle (see Fig. 824), was constructed to the south of the lady chapel. In carrying this out the south wall opposite the three westmost bays of the choir was removed, and three arches carried on two piers substituted (Fig. 843). These piers and arches correspond with the work of the same period at the east end of the choir. The vaulting is also of a similar light and elegant character, and has similar intermediate ribs or tiercerons and ridge ribs. The vaulting is raised considerably above the arches next the aisle, and is carried on caps, which have short shafts resting on corbels. One of these contains a shield bearing the three unicorns’ heads of the Prestons. [Illustration: Section of Mouldings of Window Jamb and Niche. Interior. Exterior. FIG. 842.--St. Giles’ Collegiate Church. East Window of North Transept.] [Illustration: FIG. 843.--St. Giles’ Collegiate Church. Preston Aisle.] The aisle had one large window in the east end and three windows to the south. This structure extends into the choir the great width of the four aisles of the church previously formed in the nave, thus adding greatly both to the superficial area and to the appearance of spaciousness and grandeur of the edifice. [Illustration: FIG. 844.--St. Giles’ Collegiate Church. Monument in Lauder’s Aisle.] The church, in its full length and breadth, was now complete in all its parts, as it still remains internally, with a few exceptions, till the present day. It measures internally 196 feet from east to west by 125 feet from north to south across the transepts. The choir is 68 feet in width over the north and south aisles, and the Preston aisle is 45 feet 6 inches in length and 27 feet in width. The nave, including the five south chapels, is 81 feet in length by 91 feet in width within the walls.