The vault has thirteen complete bays and two semi-bays, one at either end. The junctions between this later vault and the Norman work can be seen. The main piers had the original double shafts cut off at the level of the top of the triforium arches, the later single shaft being brought down and joined by a peculiar branch-like connection. The original shafts to the subsidiary piers, which it is probable took only a minor part in carrying the flat Norman wooden roof, were finished by a cap at the impost level of the triforium, and the later shaft was brought down and finished by the _rebus_ of Bishop Lyhart, the constructor of the vault. This _rebus_ should be noticed; it is a pun in stone, with its hart lying in water. It will also be noticed that the outer arches of the triforium are not concentric with the sub-arches. [Illustration: The Nave, looking East.] The bases of the shafts have been Perpendicularised, probably when the vault was added, and the Norman character of the lateral shafts spoilt by scraping. The building of the nave is usually attributed to Bishop Eborard (1121-45), but some eminent archaeologists believe that the whole cathedral, nave and all, was built by Herbert, 1091-1119, the first bishop and founder. We believe there is no documentary evidence against this theory. The _Registrum Primum_ says: "Moreover, the same Herbert completed the church of Norwich in his own time, as I have learned from the account of old people, _but have not found in writing,_ as far as the altar of the holy cross, which is now called the altar of S. William." The billet enrichment on the main arches, and the chevron or zig-zag on those of the triforium, have been looked upon as indicating that this part of the building--the five western bays of nave--is later than the presbytery, the arches there lacking this ornament. But as these are quite the earliest forms of ornament used by the Norman builders, their occurrence here at Norwich cannot prove much. It is better perhaps to reserve judgment, and be content with merely stating the facts and the more generally accredited theories as to the age of the western part of the nave. The subsidiary circular columns in the fifth bay of the nave from the west end should be noticed. A small enriched shaft in the clerestory of the north transept is here illustrated. This very beautiful style of treatment was common to the Norman builder, with the Romanesque, and the Romans before them.