CHAPTER VII

THE CATHEDRALS OF THE THIRTEENTH CENTURY

The Cathedral of Rheims, which was begun soon after the destruction of the original building by the fire of 1211, is a supreme expression of the fusion of the three systems--those of Aquitaine, of Anjou, and of the Ile-de-France. It may be taken as the most perfect manifestation of persistent efforts to establish a method of construction based on equilibrium--the equilibrium, that is to say, of a building vaulted on intersecting arches, the thrusts of which are received by exterior flying buttresses.

The temerity, and even the dangers of such a system, are sufficiently demonstrated in the wonderful works of the thirteenth-century architects themselves. For, notwithstanding the skill and beauty of their many admirable combinations, they were unable to reduce their methods to scientific formulæ. The statical power of their structures remained an uncertain quantity, determined by the durability of the material and its exposure or non-exposure to the weather, the interior skeleton being formed of the same material as the exterior.

The perils inherent in such a system are more apparent at Rheims than elsewhere, because of the colossal proportions of the building. The arrangement of the flying buttresses, however, is more logical than at Laon, Paris, Sens, and Bourges, by reason of the quadripartite arrangement of the main vault. The thrusts being equally distributed among the supporting piers, each flying buttress performs an identical office; their equal strength and solidity is therefore perfectly appropriate and logical. But though theoretically correct in its disposition of flying buttresses of equal strength to meet thrusts of equal strength, the method is vitiated by its inherent weakness as a system of abutment. The fragility of the flying buttress exposed it to two grave dangers, active and passive; active, taking into account the constant strain upon it as an abutment; passive, in regard to the gradual reduction of its solidity by exposure to weather. In support of this statement, it is only necessary to refer to the restorations which it has been found necessary to make within the last few years, to preserve the nave. The flying buttresses have been strengthened from below, a proceeding without which the collapse of the huge building would have been inevitable.

But we shall find much to call for unqualified admiration at Rheims in the grandiose conception of the work and in its powerful execution, in the magnificent arrangement of its eastern façade, and in the perfect harmony of the ornamentation, where sculpture, capitals, friezes, crockets, and floriations are so many types of mediæval decorative art at its best.

The Cathedral of Amiens, which dates from about 1220, and is one of the largest as well as one of the most admired of Gothic masterpieces, is directly founded upon that of Rheims. The plan is on the same lines, with this exception, that at Amiens the choir is of greater importance relatively to the nave, and that the piers and points of support are weaker and much more lofty.

The Rémois architects, while exercised by the problems of equilibrium which their system involved, sought to minimise its dangers, which they recognised no less fully than their predecessors, by prudently avoiding all false bearings. It will be easily seen by a comparison of the two sections (Figs. 45 and 48) that the builders of Amiens were troubled by no such misgivings, or that they were at least more venturesome if not more accomplished. They did not hesitate to base the columns which received the crowns of the flying buttresses on a corbel arrangement which had no solid bearing, as may be seen by following the direction of the dotted line X in Fig. 48. The boldness, or rather the imprudence of such an arrangement is patent, for the failure of anyone of the courses, or the decay of any part of the pier into which the corbels are keyed, would necessarily involve a rupture in the flying buttresses, on which the stability of the main vault depends. The disintegration of the whole building and its total ruin could be the only result. The perils of such combinations, or rather such _tours de force_ of equilibrium, are exemplified at Beauvais. The architects who built the choir, about the year 1225, basing it on that of Amiens, determined to raise a monument which should surpass, both in plan and elevation, all the structures of their epoch. They increased the breadth of the choir and of its bays, raising, in the latter, intermediate piers on the crowns of the lower archivolts, thus dividing the upper bays, and at the same time strengthening the vault by auxiliary transverse arches. They exaggerated the height of the archivolts and of the large windows, and diminished their thickness, in order to give greater elegance and lightness, and the main vault rose to a height of more than 160 feet above the ground level. This tremendous elevation, the exaggeration of which in proportion to the width of the nave is striking, necessitated a complicated system of flying buttresses surpassing in boldness all that had gone before. The section in Fig. 51 will give some idea of what has been justly described as an architectural folly. It is astonishing that the structure should have stood as it has done, taking into account the false bearings of the intermediate piers, here again shown by the dotted line X (Fig. 51).

These rest for half of their thickness on off-sets from the piers, which, proving unequal to the strain, have been temporarily stayed, and must eventually be consolidated.

The choir, however, was finished about 1270, and stood for several years. But dislocations then declared themselves. The forces so elaborately balanced lost their equilibrium, and on the 29th November 1284 the vault fell, dragging down with it the flying buttresses, and carrying havoc through the rest of the building. In the reconstruction which followed it was thought imperative to double the points of support in the arcades both of the main and side aisles, and to reinforce the flying buttresses by iron chains.

During the thirteenth century a number of cathedrals were raised all over Europe on the model of the great buildings of Northern France, and more especially of Amiens, which seems to have roused a great enthusiasm; these were, however, of far more modest dimensions. They had neither the exaggerated height nor the structural audacities of their exemplars. Few of these churches and cathedrals, the reconstruction of which on the new system generally began with the choir, which was added to the primitive nave, were completed by those who initiated their erection. The most highly favoured in this respect were finished in the course of the fourteenth century; but in the greater number of cases the work dragged slowly on, and reached its end some two centuries after its inauguration. Reconstructive undertakings were constantly impeded by wars or social convulsions, which either hampered or entirely cut off the resources of bishops and architects, their promoters. Such interruptions were of great service to modern archæological study, offering as they do distinct evidence of the various transformations which were successively accomplished from the so-called Romanesque period to the Gothic.

The majority of these great buildings, which show traces of the vicissitudes through which they passed, bear a strong likeness to each other, and vary only in detail, according to the skill of their constructors.

The peculiar interest of Chartres centres in its remarkable statuary; it has, however, other features which command attention, such as the rose window of the north, transept and the design of the flying buttresses. These consist of three arches, one above the other, the two lower ones being connected by colonnettes, radiating from a centre, so that the lower arch is related to the upper, as the nave of a wheel is to the felloes, the colonnettes forming the spokes.

At Mans the arrangement of the choir is so far more remarkable in that it is extremely unusual, or indeed, in its way unique. The flying buttresses are planned in the form of a Y (see A on the plan Fig. 53), thus affording space for windows in the exterior wall, to light the vast circular ambulatory, which at Mans is of unusual importance, and surrounds the choir with a double aisle. The flying buttresses which rise above the _arcs-doubleaux_, bi-furcated (B on the plan), are over-attenuated in section; their exaggerated height and proportionate slenderness threaten to make them spring, so that it has been found necessary to bind them together by ties and iron chains. Such expedients are a sufficient criticism of the ingenious but precarious system adopted by the architects of Mans.

The influence of the Ile-de-France in Normandy is manifest in the arrangement of choirs and apsidal chapels in Norman cathedrals of the thirteenth century. The Cathedral of Coutances, a monument of the eleventh century, was rebuilt in the early years of the thirteenth century under the impulse given by Northern France to the architecture of the period. It is in the choir that we clearly trace this influence, in the double columns of the apse, and the ingenious disposition of its collateral vaults. But the façade is purely Norman, not merely in general design, but in the details of the composition, facsimiles of which may be found in England.

The Cathedral of Dol in Brittany, one of the great churches of the thirteenth century, seems to have escaped the influences of the Northern innovation. Its general plan, its square apse lighted by large windows, the details of its architecture and ornamentation, all proclaim its affinity to the great churches which rose contemporaneously with it on either side of the Channel, in Normandy, and in England. It is very probable that it was built by the same architects or their immediate disciples, working on the more ancient methods of the Norman schools founded by Lanfranc at Canterbury towards the close of the eleventh century, on the model of those he had established in France at the famous Abbaye du Bec.