Sacred Geometry in Medieval Cathedrals: Ancient Wisdom in Service of the Divine.

To gain insight into the design of Aubertin organs, it’s important to study the origins of sacred geometry as it was applied during the Middle Ages. Bernard Aubertin devoted countless hours to the study of proportions in churches and sacred spaces. He delved into medieval texts in the attempt to understand why religious buildings from that particular era continue to captivate the modern viewer.

In his research, Bernard Aubertin discovered that the construction of Gothic cathedrals was not merely a technical feat; behind the stone walls, flying buttresses, stained glass windows and other engineering marvels lies a set of mathematical and symbolic principles known as sacred geometry. This disciple, which links geometric shapes to spiritual concepts, played a critical role in the creation of the Middle Ages’ most significant religious monuments. The medieval builders, who were often members of secret guilds, tapped into the principles of sacred geometry to create a link between heaven and earth, thus transforming the cathedrals into spiritual gateways.

The Origins of Sacred Geometry.

Sacred geometry is rooted in the belief that certain shapes and mathematical proportions directly reflect the laws of the universe and cosmic order. These figures—found throughout nature in seashells, flowers, and even galaxies—are seen as expressions of divine harmony. In this sense, geometry goes beyond being a mere construction tool; it becomes a symbolic language used to design structures that bridge the physical and spiritual worlds.

Medieval master builders imbued each geometric element in their cathedral designs with sacred significance. Basic shapes like the circle, triangle, and square were intertwined to represent various dimensions of existence and divine relationships. The circle symbolized infinity and divine perfection, while the triangle, often linked to the Holy Trinity (Father, Son, and Holy Spirit), represented unity in diversity. The square stood as a symbol of the earth, matter, and stability.

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The Golden Ratio & Divine Proportion.

The Golden Ratio, also known as the “golden section” or “divine proportion,” is one of the most iconic principles of sacred geometry. Represented by the Greek letter φ (phi), with an approximate value of 1.618, this mathematical ratio appears throughout nature—from the spirals of seashells to the proportions of the human body. It is viewed as a symbol of ideal beauty and cosmic harmony.

Medieval architects often incorporated this proportion into their designs. Many cathedrals, for instance, were built using dimensions based on the Golden Ratio. This wasn’t just an aesthetic choice; the builders believed that by embedding this ratio in their structures, they were aligning human creations with the harmony of the divine. Their aim was to create spaces that radiated peace, balance, and a transcendent sense of beauty.

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Symbolic Geometric Figures.

In medieval cathedrals, geometric shapes held profound symbolic meaning that extended far beyond their practical applications. Here are some of the most commonly used figures and their deeper significance:

The Circle: Representing infinity, eternity, and unity, the circle was a powerful symbol of God, the eternal being without beginning or end. The rose windows of cathedrals, with their stunning, circular form and intricate designs, are prime examples of this symbolism.

The Triangle: Linked to the Holy Trinity, the equilateral triangle symbolizes perfect harmony and balance. It also represents the connection between heaven, earth, and humanity, reflecting spiritual unity.

The Square and Rectangle: These shapes stand for the material world and physical existence. The square, in particular, symbolizes earthly stability and order. It was often used as the foundation for cathedral floor plans, and when inscribed within a circle, it expressed the relationship between the heavens and the earth.

The Cross: The Latin cross, the core shape of many cathedrals, symbolizes Christ's sacrifice and the union of the material and spiritual worlds. In some cases, cathedrals were designed in the shape of the Greek cross, with equal-length arms, emphasizing balance and harmony.

The Regulating Line and the Geometry of Divine Light.

One of the most interesting techniques used by medieval builders was the “tracé régulateur,” or regulating line. This geometric method allowed architects to design perfectly proportioned structures by starting from a central point and using basic shapes like circles, squares, and triangles. With these guiding lines, they could precisely position columns, arches, and vaults.

But the regulating line wasn’t just about symmetry; it was also key to optimizing natural light. In Gothic cathedrals, light was seen as a symbol of the divine. The vast stained glass windows—such as those in Chartres Cathedral—were carefully designed to capture and filter sunlight, filling the space with a mystical, glowing radiance that evoked a sense of spiritual presence.

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The Symbolism of Light and Orientation.

The orientation of cathedrals was never left merely to chance. Most were aligned along an east-west axis, with the apse facing east, towards the sunrise, symbolizing the resurrection of Christ. This orientation was believed to connect the building to the cosmic cycle and natural order, reinforcing the notion that the church reflected the broader structure of the universe.

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The Legacy of Sacred Geometry.

Today, sacred geometry continues to captivate scholars and architecture enthusiasts. Gothic cathedrals stand as enduring monuments to this ancient knowledge, often regarded as a lost art. The precise and harmonious geometric methods employed by medieval builders still inspire modern architecture.

Sacred geometry reminds us that architecture, especially that of sacred spaces, transcends mere functionality. It seeks to translate the invisible into the visible, creating environments where people can connect with something greater than themselves. The medieval cathedrals, with their perfect proportions and play of light, are timeless masterpieces that invite us to contemplate the mysteries of the universe and aspire towards the divine.

Bernard Aubertin draws upon these very principles in the design of his instruments. Using similar tools and logic, he creates works intended to lift the spirit of those who listen to and contemplate them.

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