Broken-Ribbed Chevets
After that of Saint Germer-de-Fly, perhaps the next important chevet is that of Saint Martin-des-Champs at Paris [(Fig. 65)], which dates from about 1140-1150 and may possibly be the earliest of what will be termed broken-ribbed chevets. On the exterior, this apse closely resembles Saint Germer with no flying-buttresses and only very light exterior buttress-shafts. In the interior, however, there is a marked difference between the two, for the apse of Saint Martin-des-Champs is so constructed as to include not merely the bays actually on the curve, but one rectangular bay of the choir as well. The builders thus set themselves the problem of constructing a chevet vault with seven cells, over a space greater than a semicircle. If they had made all the radiants of such a vault meet at the crown of the transverse arch, there would have been a great disparity in the length of the ribs and a very awkward shape to the separate vault cells. To avoid this, and to do away with the pressure of the radiants at the crown of the apsidal arch, the builders moved the keystone of the radiating ribs back from this crown to a point where all of them become nearly equal in length. And since the bay with parallel sides was of practically the same size as four[368] of those making up the apse proper, the keystone fell very nearly on the transverse line between the two piers marking the eastern end of this bay ([Plate II-c.]). In none of the chevets of this type did it fall directly at the center of such a line, however, and it is this fact that differentiates the chevet vaults of broken-ribbed character from the slightly later and more developed buttressing-ribbed type. A vault like that at Saint Martin-des-Champs, marks an advance over that at Saint Germer in that the two western ribs furnish admirable abutment for the keystone of the vault, and the added choir bay gives a more spacious appearance to this portion of the church.
Fig. 65.—Paris, Saint Martin-des-Champs.
There is another example of this broken-ribbed chevet in Paris, in the church of Saint Germain-des-Pres (cir. 1163), while still others may be
Fig. 66.—Vézelay, La Madeleine.
seen in Saint Quiriace at Provins (cir. 1160) [(Fig. 31)] and in La Madeleine at Vézelay (cir. 1140-1180) [(Fig. 66)]. The latter is of especial interest because it shows some peculiar makeshifts in the matter of construction. Here the choir would seem to have been originally designed to consist of two rectangular bays with four-part vaults and an apse of five sides probably with a chevet like that at Saint Germer.[369] But by the time the western bay of the choir had been built up to the clerestory, it would seem as if a new idea of a seven-part chevet had come in, perhaps from Paris, and the next bay was subdivided so as to give seven equal sides to the new vault. Then to make all the bays of the same scale, the west bay was also subdivided, but this necessarily at the clerestory level, and covered with a six-part vault. This left nine bays for the chevet and as only seven were to be actually included beneath the radiants, a narrow rectangular four-part vault was used over that toward the choir. There now remained an apse in all respects like those of Saint Martin-des-Champs and of Saint Germain-des-Pres and it was similarly vaulted with a broken-ribbed vault whose keystone does not lie quite upon the transverse line between the first two piers of the apse proper. The chevet built upon these radiants differs, however, from those in Paris and at Saint Germer in having a decidedly domed up character. In other words, the windows do not rise more than half the distance from the impost of the radiants to their keystone.[370]