It is believed that the nave was completed in the time of Bishop Riddell--that is, before 1173. This is probably somewhat earlier than the nave at Peterborough; but both were obviously being built at the same time for the greater part of the period of their erection. Both are manifestly superior to Norwich, where (to mention only one point) the excessive height of the triforium arches and the comparative low elevation of the nave arches--so that the two arcades are almost of the same dimensions--produce an unpleasing effect. But the work at Norwich was earlier, perhaps by thirty years, than either of the others. It is very difficult to obtain exact and authoritative measurements; but those usually given supply the following comparison:--Norwich, 14 bays; length of nave, 250 feet: Peterborough, 11 bays; length of nave, 228 feet: Ely, 12 bays; length of nave, 208 feet. From this it will be seen that before the tower fell the naves of Ely and Peterborough were almost exactly of the same length, while the former had two more bays than the latter. The piers are of alternate design. In front of each an inner shaft runs up to the roof. The string-course above the main arcade has the billet moulding. All the attached shafts in all three stages have cushion capitals. Under each of the large triforium arches are two smaller ones. Though it has been said that there is no trace of any change of style throughout the entire nave, yet it has been noticed that there is a certain roughness about the execution of the arches towards the east which is not seen further west. The floors of the nave and its aisles are on one level; but till recently the floors of the aisles were a few inches lower, and this is believed to have been the original arrangement. The clerestory range has three arches, the central being the highest. [Illustration: PANELS IN THE NAVE CEILING. _Photochrom Co. Ltd. Photo._]