Types of Chevet Vaults
Once introduced, four types of chevet vault were gradually established, not counting the variation which each of them underwent. For convenience these will be called the radiating-ribbed type, the broken-ribbed type, the buttressing-ribbed type, and finally the diagonal or cross-ribbed type. Each will be considered in turn and an effort made to trace their consecutive development.
The chronology of these vaults is very difficult to determine. In fact, it is probably safe to assume that the earliest example, if there were not a number of these vaults simultaneously constructed, has disappeared. In any event, it would seem that the vault must have been first used somewhere between 1130 and 1150 as there are several existing examples which date from this period. If these cannot be arranged in any certain order, they may at least, be used to show the form of the early chevets.