The west end of the nave is in part amongst the ancient portions of the structure, and the western entrance doorway is thirteenth century work.[389] The aisle windows of the west front belong to the first pointed period. The upper portion of the west front above the two large windows is of considerably later date.[390] "The design of the west front, which contains above the door-piece two large windows, with pointed niches and small circles inserted between the arch-heads, is probably original, but the upper portion and gable, including the large traceried window, are doubtless part of the restoration of the fifteenth century. The tracery of the two central windows is peculiar, and may possibly be of the fourteenth century, but that of the large upper window is later, probably of the same period as the restoration of the interior of the nave. The tracery of the large upper window is a specimen of the late kind of design employed in Scotland in the fifteenth century."[391] The interior of the west end of the nave exhibits the change of style caused by the restoration of the fifteenth century. The first or western bay of the main arcade is original, including the first arches (one on each side), the first pillars, and the arches between them, and the aisle responds. "These pillars and arches are of large dimensions and first pointed section, and appear to have been designed to carry western towers, but a part of their thickness has been cut off next the choir. A portion of the triforium wall, a piece of the string-course over the main arcade, and the corbelled vaulting shaft in the angle as high as the top of the triforium, are also parts of the original structure. The later work has been joined to the above old parts in a very awkward manner."[392] The cap of the west pier on the north side belongs to the first pointed work, while the corresponding cap on the south side and all the other caps belong to the fifteenth century restoration.[393] Except the west piers, the piers of the nave are of the clustered form, common in late Scottish work, and might be about the same date as the restoration of St. Giles, Edinburgh (which they resemble), in the early part of the fifteenth century.[394]