low, is a veritable second story above the side aisles with its own good sized windows. Its vaults are still of rather primitive ribbed type. The transverse arches, though pointed, are heavy, and to avoid the flattened curve which the diagonals would otherwise have, the vault is given a domed up crown. The cathedral of Laon (Aisne) (cir. 1170) (Fig. 48) possesses a triforium of slightly greater height but still retaining excessively heavy ribs and domed up vaults. The triforia of the naves of Noyon (Oise) cathedral (cir. 1150-1180) and of Notre Dame at Chalons-sur-Marne (Marne) (1157-1183) show a gradual reduction in the size of these ribs, all of which finally become of practically equal section in the triforium of the cathedral of Notre Dame at Paris (beg. 1163), where the doming up of the crown also disappears to a large extent and where the gallery itself is nearly as lofty as the side aisles. After the beginning of the thirteenth century, triforia rapidly decline in popularity and are but rarely found except in Normandy, where there are beautiful examples in such churches as Saint Étienne at Caen choir rebuilt in the first quarter of the thirteenth century. Owing to its early decline in popularity, the triforium never presents those complex vaulting systems of the late Gothic period which have been described as appearing in the nave and aisles. NAVE AND AISLES OF EQUAL HEIGHT In closing this chapter brief mention should be made of the series of churches in which the aisle vaults are nearly or quite as high as those of the nave, which they therefore aid in supporting. Among the numerous examples of such churches, the cathedral of Poitiers (Vienne) (cir. 1160 and thirteenth century) illustrates the type in which the vaults of the aisles are slightly lower than those of the nave, while Saint Serge at Angers has all the vaults at exactly the same level. Both are of Anjou type but this is due only to their geographical situation, for the system was widely extended.[279] In Germany there is a fine early example in Saint Elizabeth at Marburg (cir. 1235),[280] with vaulting of simple Gothic character, while the church of the Holy Cross at Gmund[281] is covered with vaulting of complex lierne type. Except for the change in interior elevation which the system brought about and the fact that it removed the necessity for flying-buttresses, it did not show any special progress along structural lines. It must be acknowledged that the churches thus constructed possess a most pleasing effect of spaciousness in their interior elevation, though this is offset by the lack of direct light in the nave. A final example of a church similar to those mentioned above but with a new vaulting system is afforded by Saint Florentin at Amboise (Indre-et-Loire) (fifteenth-sixteenth century). Its aisles are very narrow and are covered by transverse tunnel vaults in much the same manner as a number of Romanesque churches already discussed, except that the nave is here