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.
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.
BUTTRESSING. Meanwhile the increasing height of the clearstories and the use of double aisles compelled the bestowal of especial attention upon the buttressing. The nave and choir of Chartres, the choirs of Notre Dame, Bourges, Rouen, and Reims, the chevet and later the choir of St. Denis, afford early examples of the flying-buttress ([Fig. 107]). These were at first simple and of moderate height. Single half-arches spanned the side aisles; in Notre Dame they crossed the double aisles in a single leap. Later the buttresses were given greater stability by the added weight of lofty pinnacles. An intermediate range of buttresses and pinnacles was built over the intermediate piers where double aisles flanked the nave and choir, thus dividing the single flying arch into two arches. At the same time a careful observation of statical defects in the earlier examples led to the introduction of subordinate arches and of other devices to stiffen and to beautify the whole system. At Reims and Amiens these features received their highest development, though later examples are frequently much more ornate.