The eastern aisle was formerly divided by a wall behind each column into three compartments, with wooden screens in front; but these were all removed in 1814, when it was enclosed as we now see it to form the Library, which is lighted on the east by three Early English windows, and on the south by a Norman one. The western aisle appears to have been closed for many years, as on the walls built in the arches (and which until lately completely filled the openings,) there is an arcade of intersecting Norman arches. Of this aisle, thus inclosed, one portion is used as a vestry by the Vergers, having an entrance from the south aisle of the Nave; the remaining portion as a vestry for the Clergy. The carved oak door to this vestry deserves attention; it is not exactly known whether it originally belonged to the Cathedral, the carved devices are similar to those in the chapel of Bishop Alcock, in the north aisle of the Choir; there is no doubt that it belonged to some building erected by that prelate, if not to this, probably to the chapel of Jesus College, Cambridge, of which Bishop Alcock was the founder. It was found at Landbeach, and sent to the Cathedral by Canon Fardell.
The windows of the western aisle and those of the clerestory on both sides are in their original form, and so are those of the two lower tiers at the south end, but the others are of later age; in the gable is a low window of seven lights, very different to the upper windows in the north arm: those in the south end and two in the western aisle have been filled with stained glass:
The eastern window of the lower tier of the south end, by M. Henri Gerente, contains incidents in the history of Joseph; presented by the late Canon E.B. Sparke.
The western window by the same artist, contains incidents from the history of Moses: contributed by some of the then Lessees under the Bishop.
The eastern window of the second tier, by Messrs. Henri and Alfred Gerente, contains subjects from the history of Abraham, with parallels: the gift of Incumbents of livings in the diocese, and in the patronage of the Bishop.
The western window, by M. Alfred Gerente, contains subjects from the history of Jacob; the gift of Incumbents of livings formerly in the patronage of the Bishop, but not in his diocese.
The gable window contains six figures of the Patriarchs, with a figure of our Lord in the centre; some of which were executed by Mr. Howes and others by Mr. Preedy: the gift of some of the Peers and Prelates educated at the University of Cambridge.
The middle window of the western aisle, by M. Lusson; the subjects taken from the Book of Jeremiah: given by the Rev. G. Rous, Laverton, as a memorial of Dr. Hugh Thomas, nineteenth Dean of Ely.
The north window is also by a French artist, and given by the late Canon E.B. Sparke.
The piece of tessellated pavement in the floor was found some years ago between the Choir and the Lady Chapel, under the present level of the earth, and was placed here for preservation; when the floor of this arm of the Transept is re-laid, this may perhaps be again inserted, or removed to some other place.