The Divine Light of Notre-Dame Cathedral

by Allan Greenberg, appearing in Volume 48

It was a sunny spring day in May 1959 when I entered the nave of Notre-Dame de Paris for the first time. As I looked up into the seemingly weightless vaults, and then down the colonnade to the distant apse, the sheer beauty of the architecture took my breath away. Robust round stone columns with Corinthian-like capitals defined the lower nave and supported three delicate pilaster shafts, which rose up and framed the magnificent stained-glass windows and then arched breathtakingly higher to meet in the roof vault. The entire interior was modulated by an extraordinary, diffused light.

Here was formal beauty that grew out of the complex symbolism of the Catholic Church. The structure of vaults and columns, as well as huge stained-glass windows and sculpture, created a reflection of the kingdom of heaven on earth. Naive as I was, confronted by the overwhelming magnificence of this interior, I wondered whether I had died and gone to heaven.

I was a nineteen-year-old, Jewish, South African architectural student, in the third year of a five-and-a-half-year course of study. Nothing in my education had prepared me to confront a space such as this. Yes, I could draw the plans and cross-sections of the cathedral to scale and from memory. I was able to describe the program of sculpture that framed the three generous entry portals at the west front. This cathedral was a rich liber pauperum, a “poor people’s book,” in that the sculpture and stained glass illustrated biblical stories to the largely illiterate congregation.

Coming from Johannesburg, a young city of 290,000 people formed by mostly new modern buildings, I was completely unprepared for the cathedral’s majestic and mysterious beauty.

This glorious interior had to have been touched by the finger of God. I sat down on a chair in the nave in an attempt to still my mind. It was then that I realized what I was seeing: Notre-Dame de Paris, constructed between 1163 and 1345, was a perfect rendition of France’s Gothic cathedrals, characterized by an intense drive to achieve greater interior height to accommodate ever-larger decorative glass windows and the sensation of descending light. The goal was to bathe the entire interior in light. But this was not just any light. Instead, it was transformed, as it filtered through the different colors in the huge stained-glass windows, into a divine light.

Light has always played an essential role in art and architecture.  In these cathedrals, the light of heaven shapes substance—the kingdom of heaven on earth, filling visitors’ hearts with awe and enlightening their minds. Innovative architectural design features were created to facilitate this “new light,” this lux nova, that filtered its way into the cathedral’s nave, transepts, and choir, illuminating the eyes and the minds of viewers. For example, the ribbed vaults were formed by pointed arches which allowed the master masons to eliminate the walls between the interior chapels. Exterior “flying buttresses” supported the immense vaulted ceiling above and allowed outer masonry walls to be replaced with large stained-glass windows.

It was French statesman Abbot Suger who conceived the concept of lux nova and perhaps the idea of the first Gothic cathedral, the Abbey Church of Saint Denis (1144). He described the light as “wonderful and uninterrupted,” with stained glass replacing walls and creating a new, colorful way to tell the Christian story. Later, thin bar tracery was used to filter even more light through Notre-Dame’s exquisitely designed rose windows, resulting in enormous openings filled almost entirely with glass “by virtue of which the whole church would shine with the wonderful and uninterrupted light of most luminous windows, pervading the interior beauty” (David Watkin, A History of Western Architecture).

The remarkable Maurice de Sully, Bishop of Paris from 1159 until his death in 1196, took the nascent concept and form of Saint Denis further by commissioning the construction of Notre-Dame de Paris, one of the first fully developed Gothic cathedrals. Built on the site of two earlier churches and an even earlier Roman temple dedicated to the God Jupiter, Notre-Dame’s first stone was laid in 1163 by Maurice de Sully in the presence of Pope Alexander III. Notre-Dame was to be the largest structure in the known world: 420 feet long, 157 feet wide and 115 feet high—a building of exceptional size which would involve hundreds of artisans for many years. The cathedral was finished by 1260, except for the porches, though it was modified in succeeding centuries. Notre-Dame’s two towers are 223 feet high; the spires with which they were to be crowned were never added. At the cathedral’s east end, the apse has large clerestory windows (added 1235–70) and is supported by single-arch flying buttresses of the more daring Rayonnant Gothic style, especially notable for their boldness and grace. The cathedral’s three great rose windows alone retain some of their thirteenth-century glass.

As Gothic cathedrals evolved, master masons and their clients pushed their structural system of compound piers (piliers cantonnés), thin ribs and walls, stone vaults, pointed arches, and flying buttresses to the edge of their effective strength. The Cathedral of Chartres’ choir is 121 feet high; Reims’ choir is 124.5 feet high; Amiens’ choir is 139 feet high; and Beauvais’ astounding choir stands at 159 feet high—the tallest Gothic choir in the world. No wonder Beauvais became known as Icarus Cathedral, due to the lofty ambitions that led to a partial collapse in 1248.

This failure helped Gothic masons better understand the limits of their innovative structural system. We now know that wind shear forces increase exponentially with height. Resulting resonant vibrations due to high winds can cause structural failure. The masons reconstructed Beauvais’ choir with additional support columns, but the building was never finished. 

As is true of all of the world’s great cathedrals, Notre-Dame was erected as a labor of love—built to endure and teach for centuries. The roof trusses, for example, were made from heavy air-dried oak timbers that were meant to last a thousand years or more. These were taken from trees planted in the eighth or ninth century.

Knowing this made it all the more painful to watch fire devour the roof and cause the subsequent collapse of the crossing and spire in April 2019. I was stunned to learn that the roof structure, this miracle of Gothic design, had not been protected by any form of fire suppressant. This was understandable during the twelfth century, but none of the restorations in later decades included fire breaks or sprinkler systems.

Fortunately, the passing of time can bring wisdom, as well as new techniques. The current restoration includes firewalls and a misting sprinkler system, making the cathedral far more resilient and less reliant on human intervention in the face of potential hazards. The devotion of masons, timber framers, and other craftspeople, building from generations of wisdom, has been inspiring.

On that May day in 1959, entering Notre-Dame marked one of my earliest awe-struck moments as an architect, but my curiosity around the intricacies of creating a structure started when I was a young boy. I learned about the various crafts on the site of a house that my father was building for our family in the late 1940s. I would head to the site nearly every day on my way home from school, where I would pester the bricklayers and plasterers. I made such a nuisance of my eleven-year-old self that the workers eventually realized that I was genuinely interested in learning about their craft. They realized the only way to get rid of me was to teach me what they were doing.

They showed me how to set a string line so the new row of bricks would be level and the wall would be absolutely perpendicular. They demonstrated the importance of avoiding vertical joints, staggering the bricks instead, to prevent cracks and enhance strength. They taught me how to mix mortar and how to create brick patterns—running bond, English bond, and more—and how to build strong corners. By the end of the construction process, I had learned how to lay bricks, plaster a wall, and nail roof trusses together. I could put slate on a roof and build a chimney.

Once construction was complete, the personal connection I had developed with the craftsmen and their crafts changed my experience of living in that house. I felt a unique connection to the men and a reverence for their work. The cabinetmakers, bricklayers, plasterers, roof tilers, waterproofers—they were embedded in my consciousness, and there they would remain.

From that time on, I have been interested, to the point of obsession, in how a building is put together. As illogical as it seems, this is typically outside the sphere of most architects, especially today. There are usually many gaps in an architect’s drawings, and the details are laid out and resolved in the shop drawings, and shop drawings are almost always the purview of the builder. This division of duties never made sense to me, as I prefer to immerse myself in the details, start to finish. For me, these details—from the profile of the moldings to the flooring patterns—are the heart and soul of the work.

Notre-Dame and the great cathedrals of the world were created with this idea in mind—that the craft, the structure, and the ornament are inextricably linked. This conviction has remained a cornerstone of classical architecture in the centuries since. How do you put contrasting materials together to fashion a harmonious whole? What are the implications of wood, brick, and stone versus metal and glass? Will the walls be plaster or drywall? The window frames, wood or steel? The decorative elements, murals or mosaics?

I have made these decisions countless times over the course of my career, and mostly my choices have been right. I have considered beauty and light, the character of the building, and the needs of its inhabitants, focusing my attention simultaneously on both the big picture and the tiniest details.

Which brings me back to Notre-Dame de Paris on the Île de la Cité in the 4th arrondissement. In almost every French Gothic cathedral, at the end of the workday, the stonemasons carved their initials into the surface at the place where they stopped for the day. They would know where to pick up the next morning, and we would know which mason was responsible for which wall—a reflection of deep pride and ownership and an homage to the craft. Mason marks weave a subtle, very human sign in the weft of the great building.

Before the fire of 2019, some twelve million people visited Notre-Dame in any given year. My hope is that, with the great cathedral’s reopening, they will return with new eyes and an appreciation of its divine message. I am no longer young, but I hope to return there one day too. The architecture of Notre-Dame has woven herself into the fibers of my soul with a strength I feel as intensely today as I did so many decades ago.

A previous version of this article was published by First Things Online, December 9, 2024.