The sloping sides of the ceiling follow the course of the great beams supporting the roof. Till it was resolved to construct this ceiling the beams were exposed, and the whole was open to the leads. Canon Stewart speaks of it as a "remarkable example of a trussed rafter roof of seven cants," and says that such a roof was sometimes called a compass roof. He thinks it might have taken the place of an original roof of the thirteenth century.
[Illustration: THE NORTH AISLE OF THE NAVE. _Photochrom Co. Ltd. Photo._]
#The Nave Aisles.#--These retain their groined roofs. Some remains of coloured decoration may be seen in various places, especially in the south aisle; and the appearance of more elaborate colouring at one place seems to indicate that there was a side altar beneath. The rood-screen in the nave was by the pier in which is a small canopied niche. In the north aisle, beneath the windows, is an arcade of round-headed lancets, four in each bay. Above the arcade was originally a string of chevron moulding running along the whole length of the aisle; but this has been hacked off, except beneath the most eastern window. In the south aisle there are five such lancets in each bay west of the prior's door, and four in each bay beyond. The windows east of this door are higher in the wall than the others, because of the cloister, and the wall arcade is correspondingly more lofty. The chevron moulding remains in this aisle for seven bays, after which (until the last bay but one) the marks of it are clearly to be seen. One of the windows in the south aisle is original; all the rest, except one, have been recently made like it. In the north aisle all the windows are of the Perpendicular period, and have three lights under ogee arches. All are filled with stained glass.
[Illustration: THE SOUTH AISLE OF THE NAVE. _Photochrom Co. Ltd. Photo._]
In the south aisle is placed an ancient memorial stone of the greatest interest. It consists of the square base and part of the shaft of a cross. It was brought here from Haddenham, where it had been used as a horse-block, by Mr. Bentham. On the base is this inscription:
LVCEM TVAM OVINO DA DEVS ET REQVIE(M) AMEN.
Ovin has been named in the account of the foundress as being her chief agent, to whom was entrusted the civil government of her territory. There is every reason to believe that this cross was erected either by him or to his memory; and if so it must be twelve centuries old.