The Arch Never Sleeps (Dennis Aubrey)


After the fifth century collapse of the Roman Empire in the west, Europe was assailed by a series of invasions from Germanic tribes. Visigoths, Ostrogoths, Vandals, Huns, and Franks swept into what is now Italy, France, and Spain. These invasions were actually migrations of entire peoples and they settled in the conquered lands, adopting local religions and cultures while adding their own influences.. In the seventh century, the Franks became Christians and created a powerful political base that culminated in the empire of Charlemagne in the 9th Century. Under the Franks and especially under Charlemagne, there was a great Christian revival.

This Carolingian revival of religion was a combination of two great forces – the strong centralized political empire that could defend its lands and a flowering of monastic orders. The monasteries, often endowed by Carolingian leadership, were centers of learning and industry. Towns sprang up around the monastic settlements and wealth would accrue. Churches were built for both the monastic communities and for the towns.

The Carolingian-style church of Abbaye de Bénédictines Sainte-Marie, Saint-Pierre, Saint-Paul à Ottmarsheim (Haut-Rhin)

After the fall of the Carolingians, tenth century Europe underwent another series of invasions, but these were not great tribal migrations, they were pillaging expeditions from warrior cultures. Saracens from North Africa, Magyar tribesmen from Central Europe, and Norse raiders from Scandinavia poured into this land of relative wealth and sacked it time and again. The enemies were so widespread that they fought each other over the spoils. In the north, the ranging Saracens fought Norsemen. In the east, in the canton of Vaud, the Magyars fought a pitched battle with the Saracens. Europe was at the mercy of the invaders.

One of the favorite targets of these raiders were the churches, cathedrals and monasteries of the Christian world. Early medieval communities of monks wanted to build stone churches to resist the sacking of these invaders. Wooden churches were burnt to the ground and had to be rebuilt. Stone walls would resist the sacking and provide for defense. The early builders built stone walls with wood roofing structures across the nave. But these wood ceilings burned easily and fiercely, and many a church was destroyed by those determined to sack the Christian churches. Builders needed stone to cover their churches.

The wood-roofed Eglise Saint-Étienne, Vignory (Haute-Marne). This configuration was typical of Carolingian churches.

Medieval builders were confronted with two problems in building their stone churches. The first was size. In order to span an open space like a nave, they ran up against limitations on lintels. Stone lintels could span fifteen feet at the most. This meant that the width of any volume that could be spanned with a lintel was smaller than most living rooms in an American house. Needing to build larger structures, the builders looked for ways to overcome the size limitation. There were models from antiquity available to guide the builders – the Romans used barrel arches and domes to span larger spaces and the Romanesque builders copied those forms to construct the church roof with something more durable than wood.

Early barrel vault in the Abbaye Saint Martin, Saint Martin du Canigou (Pyrénées-Orientales)

The idea of a vault is so simple, a series of arches assembled in sequence to make a tunnel-like effect for a roof. But let’s look at this carefully. A single arch is a collection of shaped stones called voussoirs. They are like wedges and they make the curve of the arc. At the very top, they are capped by a central stone, the keystone. Leonardo da Vinci said that “an arch consists of two weaknesses, which, leaning on each other, become a strength.” The keystone is the source of that strength, it holds the tension of the other stones and makes the arch stable. In fact, the barrel vault is not only stable but it has the ability to span spaces of 150 feet, a ten-fold improvement over stone lintels. It stands to reason that if you have a series of arches, you further increase the stability because you are giving lateral support as well as the vertical support.

But the problem begins to arise when you think of the weight of all this stone when it covers a significant amount of space. The stone barrel vault is pretty much a “dead-load” solution to architecture. The huge mass of stone rests on heavy supporting walls which must be big and strong enough to carry the weight.

The weight, however, does not fall vertically, but thrusts sideways as well. This thrust is continuous for the entire length of the vault, and on both sides. That weight seeks to collapse, and the only thing that prevents the collapse are the massive side walls that contain the outward thrust from the vault. The higher the nave, the wider the wall at the base, because the base had to be two to three times as wide as the width at the top. This put a practical limit on the height of the nave, because the walls could only be so thick before they were ludicrously inadequate.

Eglise Saint Martin, Chapaize (Saône-et-Loire) It is possible to see here that the walls of the church near the chancel are leaning outwards under the pressure of the vaulting.

There were two solutions to this problem – changing the structure of the vault itself (see this earlier post to summarize those structural changes) and buttessing the walls to counteract the thrust of the vault.

The decision to protect the nave of the church with a vault of stone is probably the defining architectural choice for the Romanesque style. It certainly led to a church more protected against fire and pillage, but it created major challenges for the builders.

These thick supporting walls led to the second problem in constructing large stone churches – allowing adequate natural light into the large enclosed volumes. In order to have adequate light there needed to be large openings for windows. However, large openings compromised the structural integrity of the supporting walls, causing the vaults to collapse. Small windows were possible, but they didn’t generate much light at all. With the development of the rib vaults, the thrusts were directed to a series of pillars instead of the entire wall. That freed up the space that used to be used for walls to be used for windows instead.

The early churches had few windows to illuminate the interiors. Eglise de Germigny-des-Prés (Loiret)

The history of Romanesque architecture, then, is the history of the attempts to solve these two problems of size and light. Some scholars believe that Romanesque is the history of searching for the solutions, and that Gothic is the result of finding the solution. In the Gothic world, the architectural challenge changed – the purpose was to gain maximum height and maximum light. And the disaster of the cathedral of Beauvais demonstrated that the lessons were learned at great cost by even the most sophisticated builders.

4 responses to “The Arch Never Sleeps (Dennis Aubrey)

  1. Dennis this is absolutely fantastic! Two very common words to describe the photographs, no ART, and excellent historical perspective that you have assembled in this website. I would encourage everyone to learn something new at this site like I did. Great job. My best to PJ. Keep up the great work.

  2. Dear Dennis,
    Thank you for the wonderful conversation. I wonder without going into too much of the science of it what the relationship between sound, music and architecture is. I know the music was composed in the Medieval and Renaissance with great sensitivity and awareness of the reverberation. However, what I wonder is the relationship between the nature and principles of architecture and the elements and nature of how music is created. One is a creation in solid material and the other is a fluid creation in sound waves. It is rather early in the morning after a week of concerts and recording sessions, so maybe the question is posed stangely.

    Anyway, thank you for the wonderful images.

    Ray Tischer

    • Ray, here is an interesting quote from “Experiencing Architecture” by  By Steen Eiler Rasmussen:

      “”Thus, in the old churches the walls were in fact powerful instruments which the ancients learned to play upon.

      When it was discovered that the unifying tonal effect of the church as an instrument was so great that more than one tone could be heard at the same time with pleasing results, the harmonies produced by the coinciding of notes began to be regulated and used. From this part-singing developed.

      Vaults, and more especially domed vaults, are acoustically very effective. A dome may be a strong reverberator and create special sound centers. The Byzantine church of Saint Mark’s, in Venice, is build over a Greek cross in plan and has five domes, one in the center and one over each of the four arms of the cross. This combination produces very unusual acoustic conditions. The organist and compositor Givonanni Gabrieli, who lived around 1600, took advantage of them in the music he composed for the cathedral. S. Mark’s had two music galleries, one to the right and one to the left, as far from each other as possible and each with its dome as a mighty resonator. The music was heard from both sides, one answering the other in a Sonata Pian e Forte. The congregation not only heard two orchestras, it heard two domed rooms, one speaking with silver tones, the other responding in resounding brass.”

  3. Ray, there is absolutely a link between the religious architecture and the liturgical music. Some architectural historians feel that the reason that the Cluniac architecture persisted so long in building with barrel vaults was precisely because of the reverberant acoustical properties of the rounded stone vault. I have also read where the idea of transepts was based on the necessity to seat increasing numbers of the clergy in monasteries, and that antiphonal singing was developed in the church as the monks seated on one side of the altar sang one musical part and monks seated on the other sang the second part.

    As far as principles of architecture are concerned, that is a deeper subject. Clearly the materials and the structure of the volumes of an architectural space affect the acoustic properties. For example, in a Romanesque church the duration of reverberation could be 6-8 seconds. While this may have been wonderful for antiphonal singing, it could drive a modern musician to distraction.

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