The windows of the aisle are uniform in size and shape, those of the triforium are nearly similar, but all were originally lancet-shaped, but altered to their present form in the latter part of the fifteenth century. The aisle roof of the two western bays of Bishop Northwold's work (the six eastern bays) was perhaps originally as high as the other parts, but altered at a later period; the tracery of these windows on the north side remains, but on the south side there is a difference which should be noticed. The lighter style of architecture and the large windows of the fourteenth and fifteenth centuries made the support of buttresses necessary, in this instance they are deep, and surmounted by crocketed pinnacles; on the sides of many of them are gargoyles, or water-spouts of grotesque figures; flying buttresses are sometimes used in addition, reaching from the side buttresses to the clerestory walls, thus forming an important addition to the support as well as to the external beauty of the fabric: of this the exterior of the Choir of Ely Cathedral is a splendid proof. The east end of the Cathedral is one of the finest specimens extant of an Early English east front. It is divided into three stories; the lowest has three lancet windows of nearly equal height; the next tier has five windows of the same shape, side by side, the centre one being higher and those on the sides gradually lower; the third story, which is within the gable, contains three lancet windows, not seen in the Choir, but giving light to the space between the ceiling and the roof. There are several niches for statues, but no figures; and the spandrils of the window arches are relieved by quatrefoils and other ornaments. The gable point is adorned with an ornamented cross, which has been restored at the expense of Lady Mildred Hope; and a crocketed pinnacle at the south-east corner has been given by A.J.B. Beresford Hope, Esq. Rather more than a century ago this end was about two feet out of the perpendicular, but was skilfully restored by Mr. Essex, the architect. The eastern faces of the aisles appear as wings to the end of the Choir, and are flanked with double buttresses at the angles, upon which are set larger pinnacles crocketed. The windows lighting the two chapels at the end of the aisles were probably inserted when the chapels were erected; that in the north aisle is set in the wall, while that in the south aisle projects beyond the wall nearly to the depth of the buttress. The south side of the Choir is similar to the north, with the exception before mentioned--the two western bays of Bishop Northwold's work, in each of which the opening in the triforium is formed into two arches of a style differing from the adjoining portion of the building, but which have the appearance of originality. The walls of the triforium, both in the Choir and Nave were not originally so high as we now see them, but no doubt were heightened when the larger windows were inserted.