Besides its use in Lombardy and Anjou, the square nave bay with four part cross-ribbed vaults, was employed to some extent in other parts of Europe throughout the Gothic period.[168] Some of these are churches without side aisles, but aisles are more commonly found, divided into rectangular bays corresponding in number to those of the nave. Of the single naved churches, San Francesco at Assisi,[169] is a good example. Although dating from 1236-1259, its vault ribs are still heavy and almost square in section, as if derived from Lombard prototypes. But they differ in being of pointed section and in not giving to the vaults a domed up crown. In this they would seem to be examples of French influence upon Lombard tradition. SQUARE NAVE AND RECTANGULAR AISLE BAYS An early church with square nave bays and ribbed vaults over rectangular bays in the side aisles (Plate I-b), is to be found at Bury (Oise) (Fig. [Illustration: FIG. 22.--BURY, CHURCH.] 22). It probably dates from about 1125, and is an important monument of the Transitional period. Its nave vaults are quite highly domed and in this respect seem somewhat Lombard, but their pointed arches and awkward construction indicate an effort on the part of the builders toward reducing this doming and a dawning consciousness of the value of the pointed arch in the construction of ribbed vaults. This is further shown in the side aisles. Because of the rectangular shape of the bays, the problem was presented of getting three sets of ribs of different span to rise to the same or practically the same height. Not being thoroughly familiar with the flexibility of the pointed rib, the builders at Bury were naturally somewhat clumsy in its use. Thus, the diagonals were made segmental in elevation to lower them to the level of the pier arches, while masonry was piled on the crown of the transverse ribs, or their voussoirs widened, to bring them up to the level of the vault panel.[170] A few such experimental steps as these at Bury, were all that were necessary to give the builders a mastery of the use of the pointed arch in ribbed vaulting. RIBS WITH CARYATID SUPPORTS [Illustration: FIG. 23.--BURY, CHURCH.]