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INTRODUCTION
For hundreds of years the people of Europe were taught by the church that God was the most important force in their lives. If they prospered, they thanked God for His kindness. If they suffered, they begged for God's mercy, for surely He was punishing them.
In the thirteenth century God was especially good to the people of France. The alliance of a powerful monarchy and an equally powerful clergy helped spread peace, prosperity, and learning across the land. The population grew, crops were plentiful, and business was booming. There were no wars to fight, at least on French soil, and the great plague wasn't even a twinkle in some poor flea's eye. God's blessings were evident, and nowhere more so than in the cities. To express their gratitude and to help insure that He would continue to favor them, many of these vibrant and thriving communities undertook the building of new cathedrals of unprecedented scale and magnificence.
Although the cathedral in this story is imaginary, the methods of its construction correspond closely to the actual construction of a Gothic cathedral. While the builders too are imaginary, their single-mindedness, their spirit, and their incredible courage are typical of the people of twelfth-, thirteenth-, and fourteenth-century Europe whose towering dreams still stand today.
The old cathedral had watched over Chutreaux and its citizens for a hundred years. It was where many of them had been welcomed into the world through baptism, where they had come to learn the teachings of the church, and to be married, and ultimately where they had been brought to be blessed upon their departure from this earth. Its crypt was the final resting place for the city's bishops, as well as for the venerated remains of their very own saint, Etienne de Chutreaux. But as appreciated, even loved, as the building was, it was also beginning to seem a little out of date. The nearby cities of Amiens, Beauvais, and Rouen were already building new cathedrals in which the heavy walls and small windows of earlier days were giving way to slender stone skeletons and vast expanses of glass. Chutreaux was falling behind, and its residents knew it.
The final decision to build a new cathedral was made in the year 1223, after lightning struck and severely damaged the old one. With necessity now added to civic pride, the people of Chutreaux set out to build a structure as inspiring as any in all of France. The new cathedral would be built to the glory of God, and it mattered little that it might take more than one hundred years to construct it.
Although the bishop was the head of the church in Chutreaux, it was a group of clergymen known as the chapter who controlled the money. It was they who hired the widely respected Flemish architect William of Planz to oversee the project and serve as its master builder. William had gained his knowledge of architecture and engineering by visiting and working on many cathedrals not only in France but also in England and Germany.
After weeks of planning and sketching, William presented his final designs to the bishop and the chapter. The floor plan, which took the traditional form of a cross, was drawn on a specially prepared sheet of plaster. On a sheet of vellum, he had drawn a cross section of the building to show the main structure from the foundations all the way up to the roof and next to it an elevation of a typical section of the interior wall from floor to ceiling.
On May 24, 1224, the chapter gave its enthusiastic approval to William's design, and work began.
The first task was to gather the necessary workers and the masters who would oversee them. As was customary, William had not come to Chutreaux alone. He was accompanied by several of his most trusted craftsmen, including a master mason, carpenter, and sculptor. The rest of the master craftsmen were hired from the area, including a quarryman, a stonecutter, a mortar maker, a blacksmith, a roofer, and a glassmaker.
In addition to running their particular workshops, each master was responsible for the training of apprentices, or assistants who one day hoped to become masters themselves. Most of the heavy work was done by laborers, men with no particular skill. Some came from Chutreaux, some from the surrounding countryside.
Most of the tools used by the various craftsmen were made of wood and iron. All the metalwork was done by a blacksmith, and the wooden pieces were produced by skilled woodworkers.
By mid-June, laborers were busy clearing the site for the new cathedral. Beginning at the eastern end where the apse and choir would eventually stand, they removed all that remained of the old building except for the crypt, which, with its precious contents, would be incorporated into the new structure. As the new cathedral was to be much larger than its predecessor, a number of houses, including the bishop's palace, which had been damaged during the fire, had to be either demolished or dismantled and relocated.
Even while William was still designing, his master quarryman had been touring a number of sites in the Somme valley, an area rich in limestone. After comparing the quality of the stone, he made arrangements on behalf of the chapter to rent an existing quarry for the duration of the project. As soon as the plans were approved, he ordered the construction of several new stonecutting sheds and a forge where the blacksmith could make and repair tools.
As blocks of stone were pried free of the quarry face, laborers delivered them to one of the workshops, where stonecutters chiseled out the rough shape following a pattern or template supplied by the master mason. Each stone was marked twice, once to show which stonecutter had actually shaped it so that he would be paid, and once to show its final location in the cathedral.
At the same time, a master carpenter and several of his apprentices, along with one hundred and fifty laborers, were busily harvesting timber in the forest of Chantilly for the construction of scaffolding, workshops, and hoisting machines.
William wanted to be sure that by the time construction began, a steady supply of building material would always be available. Most of the stone and timber arrived by boat at the city dock, where it was loaded onto waiting carts and hauled up to the site by teams of oxen. The first sacks of lime from a local kiln were also beginning to pile up under the sloping roof of the mortar makers' shed.
As soon as the east end of the site had been sufficiently cleared, William had marked out the location of the apse and choir with wooden stakes. Now teams of laborers were busily digging the holes for the foundations, which would support the building and prevent it from settling unevenly. Around the edge of the site, and a safe distance from the excavations, and the small mountains of earth they produced, carpenters built a number of workshops and sheds in which the craftsmen could eat, rest, and work in bad weather. They also built a second forge for the production of tools and nails.
The blessing of the first foundation stone on April 14, 1225, began a construction project almost as massive as that of the cathedral itself, but one that would disappear entirely below the ground.
The first layer of foundation stones was set on a bed of pebbles and clay at the bottom of the excavation. As the blocks were nudged into place, masons troweled a thin layer of mortar between them. This precise mixture of sand, lime, and water was produced by mortar men and delivered to the masons by laborers.
With his level, the master mason continually checked to make sure each course of stone was perfectly horizontal. Any carelessness in the construction of the foundations could endanger the structure that would eventually stand on top of them.
As the masons gradually worked their way around the choir, carpenters built a roof over the crypt to protect it from the rain and snow.
When the first section of foundation was completed and its mortar had sufficiently hardened, work began on the walls above. The walls of a Gothic cathedral like Chutreaux's either rest directly on the foundations or on an arcade, a row of arches supported by massive columns called piers, which have their own foundations.
For sections of solid wall, the stone mason would actually construct two parallel walls and then fill the space between them with concrete, a mixture of mortar and small stones. It would have been too expensive to build walls of solid stone. The main piers, on the other hand, were built entirely of stone with no infill, all the way up to the triforium.
The vertical mullions and intricate tracery that made up the framework of the windows, all of which was carefully cut from templates, were cemented into place as the walls were being built. But even before the window level was reached, wooden scaffolding had become a necessity for supporting hoists as well as movable platforms for the workers. The scaffolding was made of poles lashed together with rope, and the platforms, called hurdles, were made of woven twigs.
Next to one of the chapels surrounding the apse, masons were building a spiral staircase to carry workers, tools, and even some materials up to the triforium. By the time the cathedral was finished, several such staircases would be in place, some of which reached all the way to the roof.
By 1235 many of the piers of the arcade were complete and work began on the arches that would link them. These were built of wedge-shaped blocks of stone called voussoirs over temporary wooden frames called centerings. Once the wall above each arch was in place and its mortar had set, the centering could be lowered and used elsewhere.
The smaller arches of the triforium as well as the narrow passageway behind them were built next on top of the arcade. As each section of the triforium was finished, it was tied to the top of the outer wall by a wooden roof. The aisle between the arcade and the outer wall was then covered by a vaulted ceiling. Once again wooden centerings were used — this time to build the arches that would help support the vaulting.
By the summer of 1242, the pier extensions and window tracery of the clerestory were visible. Given the scarcity and expense of very tall timbers, the scaffolding required for everything above the triforium was supported by the walls themselves rather than the floor.
William knew that the arch-shaped ceiling that would eventually cover his cathedral would tend to push the walls outward. In order to protect the walls, these destructive forces would need to be counteracted in some way. In earlier churches, the problem was solved by building heavy stone towers called buttresses right up against the walls and between the relatively small windows. But when aisles were needed around the central space, the buttresses were built away from the high walls. They were then connected to the high walls by stone arches called flying buttresses. The outward forces would travel across the flying buttresses and down through the buttresses to the foundations below.
When a section of wall and its adjacent buttresses reached a certain height, wooden centerings and scaffolding were installed between them. These would not only support the flying buttresses during their construction, they would also give the entire structure additional stability.
Even as tracery was being installed, window makers were already at work preparing for the time when they would replace the masons on the scaffolding. Most of the windows would use a combination of clear glass — to illuminate the interior space — along with small areas of decorative stained glass. A number of special windows to be filled entirely with stained glass had also been ordered. Because of their expense, these windows were paid for by wealthy individuals or professional organizations.
Since these windows were meant to tell specific stories, the window makers and clergymen worked closely together on their design.
The glass used in all the windows was made from a combination of beechwood ash and washed sand melted together at high temperatures. To achieve the different colors, particular kinds of metals, vegetation, and even old glass were added to the mix. All the glass was produced in workshops located near surrounding forests, where plenty of wood was available for fueling the furnaces.
There were two main ways of making the glass, but both began by first scooping up a ball of molten glass on the end of a hollow pipe and blowing air into it. In one method the glass was blown up like a balloon before being transferred to a solid pipe called a punti. The blow pipe was then cut free and the sphere, now with a hole in it, was spun quickly, which forced it to open up into a flat circular shape. It was then removed from the punti and allowed to cool. The second method involved blowing up the glass while simultaneously rolling it on a hard surface to form a cylinder. When the cylinder reached the right size, the ends were cut off and it was sliced down the middle and opened to form a flat sheet.
At each window maker's shop, a full-size plan for a section of a window was first drawn on a whitewashed bench. Every piece of glass was laid over this pattern before being cut to the exact size and shape using a pointed steel rod called a grozing iron. Individual pieces of glass were usually quite small, but when several pieces were joined together using specially cast strips of lead, they could form sections as large as thirty inches square. As each window section was finished, copper rods were attached to the outer face to provide additional rigidity against the wind.
On the scaffolding, window makers installed iron bars between the mullions and tracery to support the weight of the glass panels and to hold them in place. Although single pieces of glass were usually no larger than eight inches square, the finished windows could easily reach heights of forty feet or more.
In November, as in every previous winter, the stonework was covered with straw and dung to prevent frost from cracking the mortar before it had completely dried. While many of the masons went home during the coldest months, those apprentices who couldn't afford the time off worked in the quarries. Stonecutters and sculptors took up residence either in workshops or in smaller sheds between the buttresses of the choir, which were a little easier to heat. They continued shaping stones and tracery or carving capitals and statues in preparation for the return of the masons in the spring.
By 1247 the 140-foot-high walls that surrounded the choir were finished and in the autumn of that year work began on the roof, which would eventually add another fifty feet to the overall height of the building.
The roof was made up of a series of triangular frames or trusses, each of which was first test-assembled on the ground. The timbers, some of which were sixty feet long and had been imported from Scandinavia, were fastened together by the mortice-and-tenon method; holes called mortices were cut, into which the tongues or tenons of other pieces would then fit. When the carpenters were satisfied that everything would fit as planned, each truss was dismantled and hoisted piece by piece to the top of the walls.
Once the crossbeams were in place, a windlass was set on top of them to hoist the rest of the timber and help in setting up the trusses. As the various pieces were maneuvered into their final position, each mortice and tenon was locked together with oak pegs. When the completed trusses were fastened together, additional timbers were installed, to which rows of wooden slats were then nailed. Before being covered with sheets of lead, all of the timber was coated with pitch to prevent rotting.
By the spring of 1253 the roof was finished and the choir was ready to receive its vaulting. This stone ceiling would spring from the walls about a hundred feet off the ground and rise to a height of thirty feet. Robert of Cormont, who had replaced the aging William as master builder, supervised the erection of new scaffolding high up above the choir on which masons, mortar makers, and carpenters could safely work.
It was during the construction of the scaffolding that the bishop of Chutreaux died. Work stopped for seven days, and on the fourteenth of July 1253, his body was interred in a new tomb in the old crypt. On the fifteenth of September work was interrupted once again, this time for the installation of Roland of Clermont as the new bishop of Chutreaux.
Two types of machines would be used to lift the stones and concrete to the roof for the construction of the vaults. The first was the windlass, of which there were several already in place, and the second was the great wheel. It was large enough so that one or two men could stand inside. Through its center ran a long axle to which the hoisting rope was fastened. As the men walked forward both the wheel and the axle turned, winding up the rope. The great wheel was capable of lifting very heavy loads, the first of which were the large centerings that would temporarily support the vaulting until it could stand on its own.
(Continues…)
Excerpted from "Cathedral"
by .
Copyright © 2002 David Macaulay.
Excerpted by permission of Houghton Mifflin Harcourt Publishing Company.
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