[Footnote 23: This cathedral will be hereafter referred to, for the sake of brevity, by the name of _Notre Dame_. Other cathedrals having the same name will be distinguished by the addition of the name of the city, as “Notre Dame at Clermont-Ferrand.”] The masterly examples set by the vault-builders of St. Denis and Notre Dame were not at once generally followed. Noyon, Senlis, and Soissons, contemporary with these, are far less completely Gothic in style. At +Le Mans+ the groined vaulting which in 1158 was substituted for the original barrel-vault of the cathedral is of very primitive design, singularly heavy and awkward, although nearly contemporary with that of Notre Dame (Fig. 118). [Illustration: FIG. 118.--LE MANS CATHEDRAL. NAVE.] +DOMICAL GROINED VAULTING.+ The builders of the South and West, influenced by Aquitanian models, adhered to the square plan and domical form of vaulting-bay, even after they had begun to employ groin-ribs. The latter, as at first used by them in imitation of Northern examples, had no organic function in the vault, which was still built like a dome. About 1145-1160 the cathedral of +St. Maurice+ at +Angers+ was vaulted with square, groin-ribbed vaults, domical in form but not in construction. The joints no longer described horizontal circles as in a dome, but oblique lines perpendicular to the groins and meeting in zigzag lines at the ridge (Fig. 119). This method became common in the West and was afterward generally adopted by the English architects. The +Cathedrals+ of +Poitiers+ (1162) and +Laval+ (La Trinité, 1180-1185) are examples of this system, which at Le Mans met with the Northern system and produced in the cathedral the awkward compromise described above. [Illustration: FIG. 119.--GROINED VAULT WITH ZIG-ZAG RIDGE-JOINTS. _a_ shows a small section of filling with courses parallel to the ridge, for comparison with the other compartments.] +THIRTEENTH-CENTURY VAULTING.+ Early in the thirteenth century the church-builders of Northern France abandoned the use of square vaulting-bays and six-part vaults. By the adoption of groin-ribs and the pointed arch, the building of vaults in oblong bays was greatly simplified. Each bay of the nave could now be covered with its own vaulting-bay, thus doing away with all necessity for alternately light and heavy piers. It is not quite certain when and where this system was first adopted for the complete vaulting of a church. It is, however, probable that the +Cathedral+ of +Chartres+, begun in 1194 and completed before 1240, deserves this distinction, although it is possible that the vaults of Soissons and Noyon may slightly antedate it. +Troyes+ (1170-1267), +Rouen+ (1202-1220), +Reims+ (1212-1242), +Auxerre+ (1215-1234, nave fourteenth century), +Amiens+ (1220-1288), and nearly all the great churches and chapels begun after 1200, employ the fully developed oblong vault.