Samuel Kurinsky,
The Glassmakers: an odyssey of the Jews, the first threethousand years, Hippocrene Books, New York, 1991

On divers arts,
Dover Publications Inc., New York, 1963

Jean Bony,
French Gothic Architecture of the 12th & 13th Century,

University of California Press, Berkeley, Los Angeles, London, 1983

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Articoli in tema
The origins

TITOLO: Notes for a history of glass in architecture: the Cathedrals

WRITTEN BY: Lorenzo Matteoli

Edited by: Wendy Charnell

DATE: 1994


The Cathedrals
Lean, high-rise structures and sophisticated glazed envelopes are the marks of contemporary architecture. Yet, eight centuries ago, the builders of Gothic cathedrals had already explored this technology proving complete mastery of all its construction and detailing problems.
Gothic cathedrals, searching for God and challenging the laws of gravity, are the skyward explosion of the earth-bound Romanesque churches. While the builders of the 7th, 8th and 9th century sought an all-embracing relationship with the earth as the great protecting mother, Gothic builders sought the sky, issuing the ultimate challenge and thus expressing the scope of human life.
The economy of poverty and survival was behind the Romanesque churches, with the few exceptions of the ones built by powerful cities (as St. Ambrose in Milan). The rising powerful and rich merchant economy of the European traders was behind the Gothic monuments.
Romanesque churches were inspired by the serene acceptance of God as the universal and supreme power. He who giveth and taketh away good, evil, life and death is sought in peace and humility by the mystic worshipers of the eighth century. Medieval Gothic churches are the proud statement of a new human consciousness.
The rigorous logical thoughts of the Doctors of the Latin Church, St. Augustine of Hippo (354-430), St. Ambrose (340-397), St. Jerome (340-420) as spread and popularized by St. Thomas Aquinas (1224-1274) and by theologians like Peter Abelard (1079-1142), instructed the theoretical framework to reach God with the mind. The dynasties of the Parler family (Schwaben) and of the Eusingers, builders and masons for generations, a few centuries later, built the architectural monuments of this creed.
Men and women of the 11th century did not feel any more like powerless subjects, they did feel like the immanent vehicles of divine intelligence. The great spiritual power that stemmed from this perception drove individuals, moved societies, and gave birth to the ideal tension that was the brand and the legendary force behind both Medieval achievements and miseries: wars, crusades, sagas, cathedrals, monasteries, fortresses, castles, epic poems, thought, schisms, heresies, curses. The new consciousness also accounted for the spread of rebellions, revolts, unrest and upsurges that marked the first steps of the long, dire and bloody journey from a society of privileged and slaves to a society of equals and free: a journey spanning eight centuries with still a long way to go.
If art is the expression of ways of thinking, values and culture, the difference between Romanesque and Gothic architecture stands for the revolution of thought that took place in Europe from the 7th century to the beginning of the new millennium anticipating or actually setting out the foundations for the subsequent new birth of the Arts: the Renaissance.
Economic centres were moving East, new production activities were established in Central Europe (textiles, wool, silk, leather, steel, glass): new trades brought new information, new agricultural practices learned from far away countries and produce imported from the far East changed the way of living. Endemic and periodic famine was eventually to end, population increased by factors in a few hundred years. A new social class was fighting its way to recognition: the burghers (la bourgeoisie), entrepreneurs, bankers, traders, money dealers, manufacturers.
Hence the slow fading away of the relics of the Roman domination. The matter of fact, military approach of the Romans gives way to the mythical northern imagination. The ideal impulse of the culture of the Celts, with its two thousands years of tradition, again takes the lead throughout Northern and Central Europe.
Legendary heroes, fables, fairies, magic rites, dreadful curses, gentle and sometimes fearful, animistic interpretations of nature, overwhelm the vain and demanding gods of Rome.
The Gospel stories blend with the legends of the North and the spirit of the place , the ethereal tutor of architectural design, is once again a northern Genius, barbarian, and thus Gothic, a term coined by the self appointed aesthetic representatives of the Renaissance, who saw themselves as the founders of something that, in fact, had started two or three centuries before and of which they were a logical, even if magnificent, consequence.
The forest, an overwhelming presence of the great North, is the genius loci of the Gothic church. The tall tree trunks become columns, the ogive vaults replicate the arching of the branches connecting the trees high above. Light from the low northern sun filters through the long vertical breaches between the columns as it does through the trees. The forest/cathedral is home to northern imagery. Fairies, fantastic animals, ghosts, monsters peek out from every corner and receptacle. It was in the forests that Druids performed their liturgies and magic rites, that Celtic legendary heroes went to seek their glory or escape their curses. Man was alone, in the forest, and his relationship with God was personal, direct and somewhat fearsome. One name suffices to recall the many Burgundian legends: that of Sigfried the hero of the Nibelungenlied.
Pointed arches appeared as features of church and civil building construction at the turn of the millennium . Full deployment of the Gothic international style with all its accouterments (pointed arches, ribbed vaults, flying buttresses, stained glass windows and rose-windows) are to be found in the great European churches and cathedrals from the second half of the twelfth century (1150). The Gothic age, from its first signs to its maturity, lasted for more than four hundred years until the end of the fifteenth century: in terms of human life-span, approximately 16-18 generations.
Gothic art and architecture are the flowers of the Middle Age, a period of history that has been branded with many misleading generalizations and historical clichés, a period which is in fact difficult to describe due to the diverse, contradictory features: the cruel exercise of power, the mystical serenity of the monasteries, the violence of endemic warring, the destructive power of recurring plagues, the early signs of cultural rebirth closely associated with the despairing darkness of an unending curse.
The cultures behind the construction of the great Gothic churches and cathedrals are not easy to trace in the complex and fragmented structures that were the cradle of modern Europe: Roman rule, even in its Byzantine passionate and distant revival, was a long-gone memory, but some of the threads of command lingered here and there, blending with old and new local customs. The governing bodies were dynamic and fluid combinations of secular and religious powers, different, specific and peculiar to the various European regions. What we would describe today as a lose array, anarchy to some: men of war and armed bands organized on an ad-hoc basis, no central beaurocracies, no universities, no banks or financial institutes, no lawmaking institutions, justice by the (s)word of the king at best, by the whim of the chieftain at worst, the common law still at the dawn, Roman jus forgotten. Feudalism, the tree-like articulation of power from the emperor to the local lord through grant of land property and mutual assistance exchanges (fiefs) has for a long time been the generalized Middle Ages paradigm, but according to recent reviews the term feudalism is an eighteenth century invention with scant evidence to support it as being the actual governing structure of Medieval Europe. There were some contracts of a feudal kind, but none of them can be assumed as meaningful of a general rule nor as supportive evidence of it. In fact there is much more evidence to support the autonomy and independence of the castles, communes, signorie, republics, duchies, counties, margraves. Alliances were often related to family connections, but nevertheless lose and fleeting, many local rulers had binding contracts with more than one lord and the position in case of their conflict was not always a clear one.
Legendary knights like Bohemond (b.1050/58-d. 1111) the son of Robert Guiscard, young and handsome kings like Manfred (b.1232-d.1266) or magnificent emperors like Frederick II (b.1194 d.1250) organized Crusades and Wars that were to change the geography of Europe and of the World.
Young Norman lords would leave their families to seek fortune as mercenaries and fight private battles to conquer titles and castles. Strong men, thugs and brigands organized their bands to hold up travelers and pilgrims.
If feudalism cannot be assumed as a general reference model for the Middle Ages, the existence of the very privileged few, extremely powerful and rich, over a multitude of destitute and slaves, is instead a paradigm not easily deniable and supported by consistent evidence.
Rebellions and revolts were current affairs even if it is difficult to assess exactly what these movements were and how important they actually were on the basis of the contradictory historical evidence available . A grim light is shed on the whole picture when we read the edicts and bulls that granted safe life to peasants ‘at their plow’. The revolts very rarely succeeded, usually ending in blood baths or thorough ‘cleansing’ of the rebel faction. Punishment for the survivors was of appalling cruelty to set gruesome, lasting examples: clipping of hands and feet, stripping of ears, branding with fire, digging out eye balls, were standard rituals of spectacular public executions.
Everyday life for the peasants, craftsmen, merchants was hard and, for the great many, mere miserable survival.
In the far distance, the Pope and the Emperor; closer, the Bishop and the Count, in physical contact the Count’s strongmen, brigands, marauders, preaching mendicants. Violence, plague, famine, hunger, fear, cold, stench were the recurrent curses or everyday miseries of men and women of the Middle Ages.
The general dismal picture was enlightened, here and there, by exceptions: there were also just and fair lords, noble and generous men of war, rightful fighting men and knights, communes ruled by elected wise and democratic councils, regions under the illuminated and peaceful canon of the great monasteries. The essence of the Middle Ages, lacking any specific model, is the conflicting blend of violence, piety, cruelty and mystical love that nourished hate, greed, faith and vision and led the action to great challenges.
Among them, beyond the limits of time and space, the vision of the Gothic monuments: the towers, the vaults and the glimmering transparency of the coloured stained glass windows.
Indeed the most outstanding legacy of the Middle Ages to the future.
In the uncertain, multifaceted, loose and changing economic, social and political situation of the high Middle Ages, for more than four centuries and over a territory that required a 3 months journey from one end to the other, Gothic monuments had a peculiar homologous architectural set of styles. The construction of a cathedral required vision, determination, multi-generational commitment, financial planning, engineering, technical and managerial skills, site and infrastructural services (roads, canals, means of transportation).
Demanding conditions indeed, in the context of anarchy and uncontrolled random violence that was the mark of the eleventh century life in Europe. If one looks at the context in which cathedrals were built it is difficult to characterize them as a current expression of the societies that conceived them: either they are exceptional monuments that rise above the specific history of their time, or something is missing in our understanding of the Middle Ages. The construction of the cathedral was a multi-generational commitment that involved entire populations. Towns, Kings, and powerful families were indebted for decades to the donations for the construction of the Cathedral. Taxes were levied to provide the money. Roads and canals were built to transport construction materials. The Gothic culture in Europe had that deep rooted ideal force, be it religious faith or religious desperation, be it vision of a different world or the fight to change the present world: whatever it was it was there and they had it.
Thus, it is a reasonable to assume that the construction process of the great Gothic monuments was one of the main conditions of the making of Europe. In fact there is objective evidence to support the hypothesis that this process was an institution far stronger than the social and economic environment in which the cathedrals were conceived. Which is the reason why many authors refer to the Europe of the Cathedrals.
The construction of the cathedrals paid back with technical skills and induced new social values: the power of those who possessed technical knowledge, the authority of 'the man with the rule' gave rise to a new elite in the European bourgeoisie, the technical masters, the engineers, the contractors: those who took risks to carry the task through on the confidence of their knowledge and of their skills. Geometry, engineering, mechanics and physics were not futile matters for ideological musing of idle minds. They were tools of power, that allowed them to go beyond known and accepted limits, to take challenges never previously dreamt of. The age of magic and obscure powers was over. A new age was beginning.
The utopian vision of the cathedrals set forth the confidence in scientific knowledge and in engineering tools: the cultural revolution of the year one thousand, fourhundred years before the currently accepted date for the beginning of Renaissance. Authority and command were awarded on account of competence and knowledge and not by God's anointing, the concept of responsibility was the great gift of the Middle Ages to modernity, eventually the gift of the builders of the cathedrals.
Architects, building masters, clients and technology
The site of the cathedral was an institution that lasted for decades . It employed vast economic and labour resources for generations and throughout entire regions. Quarries were opened to provide marble and stone. Overall logistics and procurement required attentive management and innovative engineering. The masters of the construction (rectores fabricae) and the architects were recognized authorities: they spoke to kings, bishops and popes. Their demands were executive mandates.
All crafts were called upon by the intersectoral operation: quarry technology, heavy load transportation and handling, logging, sawmills, wood carpentry, stone and marble precision cutting and carving, glass, woodworking, metal smelting and forging.
The technological fall-out from the construction of a cathedral was vast: transportation, site handling and lifting of heavy loads, horse harnessing, pulleys, winches, bindings and fixings, ropes and hooks, evaluation and control of stresses due to stationary and dynamic loads, tracing of cutting planes on the stones and setting out of plans and cross sections, planarity of adjacent surfaces, cutting and carving tools, thermal treatment of iron tools, geometry of cutting and carving edges, wood carpentry, timber sawing, temporary structural supports; glazing, large window assemblies, glass colouring, metallurgy of lead and tin, knowledge and control of thermal movements, management, work scheduling, procurement, bidding, bookkeeping, design and engineering.
At the beginning of 1200, architects with reliable experience were difficult to find. Construction masters and clients were trying to lure them from other sites to be able to start their own projects. Jealousies and rivalries between architects and masters were the order of the day. Building construction science was based on the ancient Roman heritage (Vitruvius), whereas scientific structural knowledge came from the Islamic mathematical tradition and from the ancient Greek texts collected by the Islam libraries, recovered and translated by the Monasteries after ‘la Reconquista’ of Spain by Charlemagne and his Dynasty. Sophisticated Geometry was mastered by Medieval Architects and Stonecutters a knowledge which is well documented by the drawings found in Historical Archives of various cathedrals and sometimes traced and carved on the very walls of the buildings.
The professional roles on the Medieval site are not always clearly set out by the literature:
Client: according to the political organization may have been any of the following: the King, the Prince or Duke, the Abbott, the Council of Canons, the City Council, special ad hoc Councils nominated by wider ruling bodies
Site Master: responsible for procurement, site programming and personnel. This role often overlapped with the role of the Client. Powerful Abbotts like Suger and Sully were the ‘de facto’ Site Masters stretching their role from financing decisions and responsibilities, procurement and contracting to engineering and design decision making.
Architect: responsible for the design and in charge of Client relations, technical supervisor, coordinator of the various crafts operating on the site.
Stonecutter: responsible for the procurement of stones, stone cutting, tracing, setting out and building, controlling the carvers and superintending lifting and handling of cut stones and sculptures, sometimes the authority of the stone cutter exceeded the authority of the architect;
Glass Master: supplied coloured glass windows and was responsible for the whole process from the rough coloured glass bulks to the assembled window.
Any one of the professionals would bring his own staff of skilled craftsmen. Unskilled labor was usually supplied locally. As happens today, the stronger personality took the lead, which was not always an easy and smooth process.
The site of the church or cathedral was also the site for most of the complementary productions: stained glass, blacksmiths, lead smelting, stone cutting, stone carvers, sculptors, carpenters all had their workshops close to the building and most of the workers had their living quarters there as well. The building rose among a cluster of barracks, huts, workshops, yards: as if it had roots connecting it to the region around and feeding it with a daily flow of components and materials.
Stone cut construction came to Europe from the North. It was the main technology for the construction of Gothic monuments and was brought to France and England by the Normans around the year 900.
The heavy buildings supported by columns demanded good knowledge of foundation technology which the Gothic builders acquired through some tough experience : excavations carried out by Viollet le Duc or during contemporary restoration works demonstrate that they knew how to distribute concentrated weights in order to avoid differential settlement and pay careful attention to the soil bearing capacity. Trial pits were dug to assess soil geology, and the same geological layer was used with great wisdom. Knowledge and wisdom sometimes were not enough and buildings collapsed, especially when their height was exceptional. (Beauvais crossing spire). The history of some of the churches like St. Pierre cathedral in Beauvais, is the history of a particularly tormented learning process by trial and error.
Gothic churches required huge quantities of wood for their construction. Tall trees were necessary for temporary supports and carpentry. Since long trunks were difficult to find and expensive the scaffolding generally did not reach the ground, it was hung to the walls and lifted when construction progressed. Permanent spiral stone staircases were built in the thickness of the walls and were used for access during construction.
This is a story directly taken from Abbot Suger diary on the construction of St. Denis (Suger ‘De Consecratione’, 1140)
(quoted by Jean Gimpel in ‘La Revolution Industrielle du Moyen Age’, Le Seuil, collection ‘Points Histoire’, Paris, 1975, translation of the author)
" Searching the timber for St. Denis carpentry
To find the beams we consulted the carpenters at our place and in Paris and they told us that according to them in the region on account of the lack of forests it was impossible to find any, and that it would have been necessary to have them transported from the region of Auxerre. Everybody agreed on that, but we were very worried by the thought of such a huge work and of the long delay that would derive to the construction; one night , coming back from the matins, I started thinking in my bed that I, myself, should have gone through the nearby woods, look everywhere and cut down construction time and any delay finding the beams. So leaving any other problem behind, one day, very early in the morning with the carpenters and the sizes of the beams we needed, I went to the forest of Rambouillet. While going there through the valley of the Chevreuse I questioned all the ‘sergeants’ and guardians of our lands who knew the forest well, if we stood any chance to find beams of the wanted size. They looked like smiling and certainly if they could they would have laughed out loud, for the wonder of our ignorance that there was nothing in that region. Even more so after the Castelan of Chevreuse, Milon, who was our man and kept for us half of the forest, had been at war with the King and with Amaury de Monfort, did not leave anything intact and in good shape having himself built high defensive towers. As far as we were concerned, we rejected all the stories that were told to us and with great audacious trust, we started to roam the whole forest. After one hour we found one beam of the right size. We did not need anything more to continue the search, before noon, and maybe earlier, in the very deep forest to everyone’s astonishment, we found twelve beams: that was the number needed. We had them immediately carried to the holy basilica and placed to cover the new building to the admiration and glory of our Lord Jesus who deserved them with all the Martyrs, since he protected the beams for us against the thieves"
Steel ties had a major role in the Gothic structural solution: some of them have been removed during recent restoration. The most extensive and sophisticated steel ties system was in the Parisian Sainte Chapelle (construction ended in 1248). Probably the earliest example of stone masonry associated with steel ties was in the Soissons Cathedral (southern arm of the transept) that dates back to 1170.
The Gothic builders perfected the site machines known by the Roman builders with remarkable ingenuity. The wheel crane was then the current lifting technology. The size of these machines must have been impressive, with wheels up to 8 metres in diametre that hoisted loads of several tons (with a 2.5 m wheel one man could lift up to 600 kg). Weight-balanced lifting cranes were also widespread.

The windows
The problems of manufacturing a large number of windows of the same size, with the same armatures, with the same adjacent components, suggested solutions that were the embryo of industrialized production. The cartons and the models for the repetitive decorative elements were a precious asset of each master and of each shop, sometimes transmitted for generations in the trade. Each master jealously guarded the models of his masterpieces, Madonne, Apostles, Christ faces and figures, eventually adapting them to new commissions. These items were the software of his trade.
The technology fall-out continues today because maintenance of the cathedral yields precious data and knowledge on the behaviour of stone load bearing structures after centuries of life, on interaction between climate and building materials, on aging of various building construction materials ...
The feature of the style is the concentration of vertical compression stresses to specific lines and enhancement of the vertical vector with the weight of the pinnacles to contain outward thrusts created by the arches and support them with leaner vertical columns and walls. The architectural elements of the gothic construction are designed by these requirements: ogive vaults, buttresses, flying buttresses, pinnacles, lean vertical columns. The heavy walls of the Roman churches, needed to contain the forceful outward thrust of the round Roman arches and vaults, are gone. The heavy masonry gives way to windows or to light marble lace decorations. Glass came as the ideological and technological answer to the problem. The huge stained-glass pictorial windows illustrating the Gospel and the life of Christ and of the saints were also amazing and powerful teaching tools, very popular with the sponsors.
The tall windows of the gothic cathedrals are an interesting example of technology/design, or problem/solution circularity: the concentrated vertical load bearing structure made thick walls obsolete and required a light closing component. Or else: the condition to host huge stained-glass pictorial windows suggested and promoted the concentration of vertical loads... problems requiring solutions; solutions creating new problems; the cycle of innovation.
Gothic pictorial windows are a unique item of Medieval Europe with no other known examples in the ancient world. Not only art, technology and architecture converge in their making, but many other disciplines and trades as well. Representing the events of the Bible requires theological background, the composition of the illustrations, the positioning of characters and figures demands cultural knowledge and political wisdom. A lot of complementary information is supplied by the accessory illustrations and decorations: the pictorial windows are vast archives and visual evidence on habits, costumes, material history of the Middle Ages. The families, princes or guilds that sponsored them wanted their specific messages to be conveyed to posterity: sometimes these messages had strong political relevance.
According to literature and excavations, the Romanesque basilicas of the 6th and 7th century were already equipped with stained-glass windows (Lactantius, Prudentius and St. Jerome). The poet Sidonius Apollinaris (5th century) describes coloured glass windows in Lyon. Pope Leo III (795-816) ordered coloured glass windows for St. Paul's basilica in Rome. The Cathedral of York in England had coloured glass windows as early as 669.
Early Christian churches had small openings filled with marble or thin alabaster slabs, some featured wooden boards pierced with holes with coloured glass inserts.
The idea to illustrate the Saints and the holy Gospel so that the windows could become a tool for the education of the early Christ pushed the technology to higher achievements. A clever idea, typical of the practical culture of Medieval monasteries: windows protect the interior space of the church and at the same time illustrate the glory of God. Besides, with clear glass windows the light inside would have been too bright, disturbing the concentration needed for prayer.
The technique of joining different pieces of glass with lead to make stained-glass pictorial windows is thoroughly described in the Diversarum Artium Schedula written by the monk Theophilus between 1110 and 1140 (see note 34 in Part 1).
The full size model of the window was drafted on a white-washed surface, each coloured part being associated with a piece of coloured glass. The glass was cut on the model using a red hot iron. The hot iron would start a crack on the edge of the glass and was moved to outline the wanted design. The crack allowed the master craftsman to break away from the sheet of glass a part that was then grozed to exactly match the drawing. Once all the pieces were set on the table, the details of the drawing were painted on the glass with vitreous enamels and the pieces were put into a kiln for the enamel to melt on the glass and to eliminate any crack left on the edges by grozing. The slow cooling cycle annealed the glass for maximum resilience.
The pieces were again placed on the table and joined with lead profiles, the cross section of which had the shape of an H. The lead ends were soldered and a sealing putty was rubbed under the leads for waterproofing and to prevent tinkling when the wind swept against the windows, which may have disturbed the prayers in the church.
Colours were obtained by mixing metallic oxides in the molten glass: copper for ruby, cobalt for blue, iron for green, manganese for purple, antimony for yellow. Glass sheets were produced with the early cylinder method in sizes of 25 x 30 centimetres and they were of a thickness varying from 3 to 8 millimetres. Specific colours (such as red) were obtained by 'flashing' the cut pieces: the method consisted of the immersion of the hot piece of glass into melted coloured glass so that a very thin layer of coloured glass would cover the surfaces.
The pictorial panes obtained were very heavy and flexible on account of the lead joints and they required iron holding frames (armatures ) to resist wind. load and stresses due to their own load during handling and transportation. In the early gothic windows the reinforcing frames were functionally placed where needed with little, or no respect at all, for the figure. In later times the reinforcing iron frames (armatures) became part of the composition as the lead profiles had been since the beginning.
With the desire of the sponsors for larger illustrations and pictorial wind the mastery of the art of coloured glazing grew as well. The figures of the prophets in the windows of the Augsburg Cathedral (1125) measure only 1.1 square metres in area, the 'Crucifixion' window at Poitiers (1163) contains approximately 16.3 square metres of stained glazing, whereas the 'Life of Christ’ in Chartres (c. 1325) is 23.2 square meters in area. The subdivisions of the holding frames were much more sophisticated and consisted of vertical and horizontal elements that subdivided the illustrations according to a logical set of images.
The technique and the mastery of pictorial windows became very sophisticated and one can refer to them as to a complete integrated building system: in the great Gothic cathedrals of the 13th century the large rose marble windows, the vertical stone mullions, the marble lace filled by coloured glass, figures, scenes, frames were so elaborated that any distinction between masonry and fenestration was virtually impossible.
The unity of the final masterpiece required close coordination and understanding among the various crafts: iron framing, stone masonry and marble laces, glass colouring processes, glass cutting, grozing and joining, had to work together with a very efficient cross flow of information.
The stained-glass windows at Chartres are an example of how the technology was mastered in the 13th century: 2,500 square metres of surface in 176 windows, three rose windows, each more than 12 metres in diameter.
Nine different masters and their workshops worked at Chartres, that was completely glazed in less than 40 years (1203-1240)
The problems to be solved for the construction of these impressive components would be a challenge for contemporary engineers: weight, differential thermal movements, wind load, water tightness, fatigue, joints to adjacent components, corrosion, and the problems related to glass durability of colours, fragility, durability of the glass itself, not to mention the clients! The clerics supplied the masters with a program to which they had to comply. Preliminary drawings were proposed to obtain the approval (called with the Latin term 'vidimus' = we have seen) and consequently transferred to full size cartoons. Technical innovations, new colours and processes that took place during the long period needed for completion, certainly implied contracting and administrative problems.
Perusing the vast literature available on Gothic cathedrals, it is clear that most of the attention of researchers and critics is devoted to the iconography and to the meaning of the images, with little concern for technical details. With the formidable exception of Viollet le Duc, architect and builder of the eighteenth century, almost everyone considers at length the colours, the structure of the figures, the composition of the illustrations and their evolution from the early examples to the great churches of the 14th century. Great attention is also given to historical meanings, messages and theological statements: the windows are in fact powerful archives for historians. The dynamic interaction of the stained-glass windows with sunlight is also a matter of attentive description. Some authors describe with passionate detail how the blues and the ambers and the reds of the Sainte Chapelle vary during the day with the movement of the sun, and how the light in the church softly turns from the vivid brightness of the morning to the subdued tones of the afternoon. Very little is recorded about the construction details that made the magic possible: about the fastening technologies, about the joints and about all the problems that the medieval builders (rectores fabricae) faced and solved to set out hundreds of square metres of heavy glass curtains, to withstand wind, driving-rain, weather and aging. Seven or eight centuries of operation are witness to the professionality and the skill of the medieval engineers. Some of the great stained glass windows have been restored with little respect for the original artifact; some have been damaged beyond repair during the wars, some have been destroyed and substituted with clear glass by the Abbotts of the Renaissance who just wanted ‘more light’ into the church; some have been stolen, sold or replaced.
A great number of these treasures was destroyed during the 1500 as sacrilegious supplements to idolatry, windows were sometimes saved because of their ... usefulness. In 1577 William Harrison in his ‘Description of England writes: ‘Monuments of idolatrie are remooved, taken downe and defaced; onlie the stories in glase windowes excepted, which for want of sufficient store of new stuffe, and by reason of extreame charge that should grow by the alteration of the same into white panes throughout the realme, are not altogither abolished in most places at once.’ Not by intelligence were they saved, but thanks to avarice and to cold...Later another crusade against religious images was spurred by the Puritans. In 1643 the stained glass windows of Norwich Cathedral were destroyed and so reads the diary of Mr. William Dowsing, commissioner of the British Parliament: ‘Sudbury. Gregory Parish, 9 January. We have destroyed ten large glass angels. The total is now 80. Eye, 30 August; seven superstitious paintings in the choir and in the transept, one depicting Maria Magdalena, all of them in glass, and six in the windows of the church.. Many other windows had already been destroyed.’
But some are still there or visible in museums throughout Europe and their story still inspiring. The details clearly show that their success is due to the simple, hands-on, ingenuous approach that was typical of medieval technology and know-how.
The windows were the product of team work. One master generally headed a team of three to four helpers and assistants and was responsible for the whole process from the design of the cartoons to the colouring, cutting and mounting of the glass on the lead jointing profiles. He supervised the crafting of the steel frames (armatures) and the subsequent setting out of the heavy and delicate component in the masonry frame. Many such teams worked at the same time on the site of the cathedral, called upon by the powerful clerics in order to complete the job in the shortest possible time. The practical scope of the clients brought together masters from all over Europe and supplied the opportunity for important exchanges of knowledge, craft secrets and subtleties: we call them "workshops" today.
The masters called by Bishops and Kings on account of their fame traveled throughout Europe. Some of the names have been recorded by history, some were never recorded. Very seldom they signed their works for conscious humility and out of respect for the cathedral (house of the Almighty). Some of them were legendary characters and rich; some obscure and humble. John from Lincoln and John from Chester were the glaziers who between 1350 and 1352 completed the St. Stephen Chapel at Westminster. Gherlachus was among Germany’s most important craftsmen in the trade at the turn of the XII century. His work is rich in colour and design, gracefully drafted figures on beautiful complex backgrounds. According to the learned critics, Gherlachus, who probably came from the Middle Rhine, directed in his old age the manufacturing of the stained-glass windows of the Strasbourg cathedral. Other masters are only known by their works, like the three main ones that worked at Chartres: the Master of the Good Samaritan, the Master of the New Alliance, and, probably the most outstanding for Gothic modernity, the Master of St. Stephen Relics. With the Masters of Saint-Eustache and Saint-Cheron, and the brilliant Master of the Saints Protasius and Gervasius in Le Mans, they have to be recorded as the most important European painters of the 1200s.
The windows were sometimes commissioned by Bishops, Kings, noble or rich families who paid for them and wanted their specific message to be recorded. Sometimes they were sponsored by Trade Guilds or Craft Corporations: these are rich pieces of information on the material history of the Middle Ages, for they depicted the crafts, illustrated the shops and sometimes recorded technological details or customs, otherwise undocumented.
The great gothic pictorial windows mark the beginning of one of the highest moments in the history of light in architecture.
Deep, intense reverence for a God of great might lingers in the great naves. The columns dissolve in the darkness above and the light, filtered by the holy illustrations, lives in magical, changing colours. The feeling of the divine is here. Voices whisper while the timeless praying chants and lauds echo from the vaults as directly reverberating from heaven, singing to earthly misery...gloria in excelsis Deo... but the daring arches, the high vaults and the huge windows are, at the same time, a proud statement of human skill and mastery: a clear sign that the Renaissance and its new values were already born in Europe.
St. Denis
Suger was born in 1081 near Paris of peasant stock. He showed outstanding intelligence from childhood and was sent to the nearby abbey of Denis to study with the monks. The school was attended at the same time by the young Louis Capet, who was to be crowned King Louis VI in 1108. The two young boys became close and very affectionate friends, a relationship and mutual understanding that was to last throughout life, with some consequence for the history of France. Suger became secretary to Abbott Adam, but, more important, he became the closest and most authoritative counsel to the King. In 1122 Suger, then aged 41, was elected Abbott of St. Denis. He strongly believed that a close association of the Abbey to the French crown could unite the nobles to their King and greatly enhance the strength of the Kingdom on account of the great symbolic meaning of St. Denis, the Saint that brought Christianity to Gaul. In 1124 the Holy Roman Emperor Henry V invaded King Louis VI territories. Louis rode into battle carrying the banner of St. Denis, the Oriflamme. The appeal to the veneration for the Patron Saint of France, strongly supported by Suger’s authority, mobilized all the nobility to the side of Louis: the largest army that had ever pledged allegiance to a French King. The sight of the French field under the Oriflamme was so formidable that Henry V decided to yield the ground without battle.
As Abbott of St. Denis, Suger, urged by Bernard, abbot of Clairvaux, established a more severe lifestyle for the monks notoriously behaving in a rather lavish and secular way. Suger and Bernard were close friends, the latter being close adviser to the Pope and probably the most authoritative spiritual leader of Europe at the time. In 1137 King Louis VI died and his son Louis VII did not accept Suger as close counsel. In the following years Suger was able to dedicate all his efforts to the construction of the new Abbey: his intelligence, conceptual strength and versatility is behind all the important architectural and technical choices. St. Denis is an original example of a new structural asset of the gothic vaults, of the stone ribs for the concentration of stresses and of the extensive use of stained glass.
In 1142 Louis VII clashed with Thibaut count of Champagne, a powerful feudal lord with many followers in the French nobility. Irrational, arrogant and with no military experience, Louis VII was not up to the task. When the situation got desperate Suger stepped in with authority, assuming command and curtly putting aside the distressed King. He rapidly got the situation under control and negotiated a peace treaty between Louis VII and Thibaut that saved the Kingdom of France from sure disaster. The treaty was signed in St. Denis, at the dedication ceremony of Suger’s masterpiece, the new architectural gem of France.
Louis VII was urged by Bernard of Clairvaux, as a penance for the high death toll of the vain war, to finance and lead a Crusade to free the Holy Land from the Muslims. Suger was very worried about the weak financial situation of the Kingdom after the civil war and tried to oppose the project, with no success. He found himself against the Pope and against Bernard and had to yield.
Louis VII and Queen Eleanor of Aquitaine left for the Crusade on June 11, 1147 and left Suger as regent of the Crown. The Crusade was to end in a ghastly and expensive disaster, but the Kingdom under the wise government of the intelligent Abbott flourished. Suger reviewed the taxation system, passed edicts for the prevention of deforestation, controlled a revolt of the nobles that wanted to make Robert count of Dreux and brother of Louis VII, king in his absence.
When Louis VII came back from the Crusade the general assumption was that Suger would not return the crown: which instead, with great loyalty, he did.
In 1150 Bernard and Suger, who, in the mean time, had changed his mind on crusades, were making plans for another Crusade, but, at the age of 70 Suger fell ill with malaria and died in January 1151.
The Abbey of St. Denis, jewel of gothic architecture in France, and the early unity of the French kingdom were the legacy of the great Abbott Suger whose power came from intelligence and from his childhood, affectionate friendship with a boy who was to become king.
By chance, or was it the outcome of the farsighted wisdom of the monks who prepared their future, intelligent and powerful, Abbott, favouring his friendship with the future king?
The Abbey of St. Denis (in the city of St. Denis now a northern suburb of Paris) was founded by Dagobert I, the last Frankish King of the Merovingian dynasty, in the year 751. Abbot Suger in 1136 built a new Basilica that incorporated the earlier Merovingian church. The church built by Suger is currently regarded as the model building of French Gothic cathedrals (such as Chartres and Notre Dame) and in general of all the later French Gothic architecture.