After the Nine Altars was finished and the connecting part between it and the choir completed, a new vault was put on to the choir, and the whole of the original Norman vault was taken down. The reason for this was almost certainly an artistic one: the sumptuously decorated vault of the Nine Altars being of a pointed form, while the original plain vault of the choir was semicircular, it would have been very difficult, if not impossible, when the great transverse arch was taken down, to bring these two forms into harmonious combination. It was replaced by one which to a great extent in its mouldings and decoration corresponds with that of the Nine Altars. This vault is in five compartments, and has four richly moulded transverse arches in addition to the eastern arch of the crossing. These arches are supported alternately on the main vaulting-shafts, which rise from the floor, and on triple shafts, which rise from the level of the triforium floor, and originally received the diagonal ribs of the Norman vault. The diagonal ribs spring from the outer shafts of the three semi-shafts and from the corresponding outer shafts next to the main vaulting-shafts. The vault is quadripartite, but in the eastern bay is an additional rib on each side--a quasi ridge-rib, which runs north and south from the spandrils between the clerestory arches, and unites at the intersection of the diagonal ribs. The additional rib on the north side springs from a draped male seated figure, on each side of which is a lacertine creature with its back to the figure, and its head turned so that the mouth touches the hair, while the tail curves towards the feet; that on the south side springs from an angel. The wall ribs spring from shafts of Frosterley marble, resting on inserted corbels or on the capitals of the Norman vaulting-shafts. In the eastern angle of the eastern bay the wall rib on each side springs from the head of a small canopy, which contains a sculptured figure; that on the north side a demibishop blessing; that on the south the upper half of a male figure. Whatever difficulty, however, there may have been in collecting the necessary funds for the erection of this noble addition to the church of Bishop William of St. Carileph, first projected by Bishop Poore, no expense or pains has been spared in its being carried out to perfection, and the vault of the Nine Altars and choir, the last part of this great work, with its enrichment of dog-tooth ornament of various and graceful forms, and bosses of foliage and figure subjects, fitly completes the building in a style no less beautiful and effective than the walls which support it. It may be asserted without fear of contradiction that no more effective or majestic vault crowns any church in our country.