Sacred Geometry in Gothic Cathedral Construction
The Gothic temple, relying on the power and symbolic capacity of geometric forms, realizes an extremely dynamic, versatile and structured constructive system from a technical standpoint, while simultaneously being profound and articulated from a theological perspective, symbolically invoking the forces of the Celestial Temple and assimilating them in earthly construction. The Gothic Temple thus experiences a close and indissoluble relationship with the Archetypal Cosmos. Everything in the Gothic temple has been designed, deliberated and realized to vibrate with it. Its construction symbolically reproduces creation, its elements the powers, the liturgy its function. We can therefore say that the essential lines of cathedral construction symbolically retrace those of the Creation of the Cosmos, as well as those of man's spiritual realization. In this perspective, the symbolic construction of the Gothic Temple can be divided into six progressive phases in symbolic analogy with the six days of Genesis: **The Foundation of the Temple** - Site selection - Determination of the vertical axis - Orientation of space or "square of heaven" - Quadrature of the primitive circle or "square of earth" - Construction - Consecration These six traditional phases do not originate with the 13th century but are much older, being fully and minutely described in the Roman period by Vitruvius in his De Architectura. In the first book, Vitruvius summarily describes these primary operations as a decisively consolidated part of architectural practice that plausibly must have dated to a much older time, probably of Egyptian origin. The first phase for temple construction consisted of site selection accompanied by the necessary work to level the ground and prepare it for the first construction operations. Once the site was prepared for temple construction, the Master Builder proceeded by erecting a column on the ground, sign of the achieved unification between the celestial temple, interior temple and terrestrial temple. To establish contact with the ordering powers of Heaven, a connection is made that unites and seals the function of the three regions of the Universe. It is from the existence of this vertical axis that the temple's mediating function derives. Just as Spirit governs Matter, the vertical axis organizes horizontal space. The act is symbolized by the erection of a column realized by the Master Builder. On the base of the center incarnated by the column, the master builder traces a circle that manifests the horizontal. The cathedral, though still unexpressed, is already entirely present in this first magic circle realized by the Master Builder. Subsequently, the temple must be oriented according to the four Cardinal points, symbol of the four universal powers that organize and arrange Nature. The orientation of sacred space occurs through the shadow of the column. At dawn of the chosen day, the sun rising on the horizon projects an earthly shadow that intersects the traced circle at a point which, united with the point found at sunset, allows determination of the East-West axis. Conversely, the point of maximum elongation of the shadow determines the North-South axis, thus completing the orientation procedure. By further dividing each quadrant into 4 equal sectors, we thus obtain the Rose of Winds described by Vitruvius in his first chapter of De Architectura. This primary phase of temple orientation is called the tracing of the "square of heaven". The celestial square is generated from above through the mediation of the central column that translates and identifies on earth the four cardinal points, thus providing the fixed orientation and dedication of the Temple, that is, the will of Heaven. The "square of heaven" thus expresses the "will of heaven" that qualifies, validates and enables sacred space, making it suitable to become the base for defining the temple. The sun itself with its action through the column determines and orients sacred space, harmonizing it with Celestial Powers. **The Construction Module** Every cathedral has its own individual character. Each cathedral develops a specific argument that may consist of a spiritual theme, a virtue, a character or a divine force that is reflected and dominates in the construction and furnishing of the entire cathedral. This inspiring idea translates, from a constructive standpoint, into what is called the cathedral's "module". The module is, first of all, the geometric incarnation of the idea and inspiring force at the base of construction. From a practical standpoint, it is a special proportion or symbolic geometric form on the basis of which the entire cathedral will be harmonized. **The Plan of Reims Cathedral** To give concrete form to this discourse, we present the construction model of an actual cathedral: that of Reims Cathedral. The module of Reims is 6/5, which gives a special symbolic coloration to the cathedral. The 6 is the symbol of the Universe, of universal Man, in relation to 5 which is the symbol of Man, the microcosm or individual Man. The symbol of number 6 refers to Royalty, Beauty and the heart, while number five to Empire, Will and spirit. This cathedral was in fact the traditional place of coronation of the kings of France, and the particular theme to which this cathedral is dedicated is that relating to the divine origins of royalty. Through geometric operations involving the golden ratio and musical proportions 3/2, the entire cathedral plan is generated from the central "square of earth" and expanded according to harmonic and musical amplification. **Musical Elevations** For the cathedral's elevation, musical proportions assume a primary role, which according to the aesthetic canons of the era translated musical harmony into visual eurythmy. The builders of 12th and 13th century cathedrals relied predominantly on those chords identified as perfect by St. Augustine and taken up by the school of Chartres as well as by St. Bernard of Clairvaux. The same operations involving the numbers 3/2 and φ are then used for cathedral elevation construction. The height of nave columns is obtained by multiplying by 3/2 the distance between one column and the next, arch height is obtained by multiplying by 3/2 the column height, and so forth.