Abstract
Most of main churches of Early Gothic were covered with sexpartite vaults. But they were deserted with transition to High Gothic, instead rectangular quadripartite vaults came to be widely employed. However in Ile-de-France, before Early Gothic, rectangular quadripartite vaults had already been used in many churches. That is to say, within the limits of Ile-de-France, the nave vaulting was suddenly transformed from rectangular quadripartite to sexpartite with commencement of Early Gothic, and then returned to rectangular quadripartite again. It is a singular transition. The transition as such cannot be explained reasonably as a development of vault. I think that the cause of such a irregular transition of vault exists rather in the transition of pier system than in the vault itself. In this paper, I make it clear that the transition of pier system in Ile-de-France is able to be recognized as a process that heavy compound piers were replaced by stages with slender columns, and that the transition of vault like above can be explained as a secondary phenomenon following to the transition of pier system.
