Sacred Geometry and Numerical Symbolism in Medieval Abbey Architecture
circle (Fig. 6). This ancient method preserves and expresses profound symbolic and operative knowledge, here summarized: The two intersection points of the circles are, symbolically, the gates where the two Idea-Forces expressed by their respective Numbers come into contact in form, passing one into the other. This interaction generates a line that expresses the metaphysical product of the union of these two abstract Ideas, visualized and applied in sacred space through the theurgical action of the priest-architect. We say units because we do not actually know the unit of measurement used by the builders in designing the building. The only thing we can verify is the ratio between the two circles, which is $8:7$. A further investigation into the units of measurement would lead us to note that the diameter of circle $C_1$ has a dimension consistent with an absolute value of 32 Hebrew cubits (normally estimated at 44.45 cm), bringing the second circle to a diameter of 28 cubits. However, we leave these leads to medieval historians, limiting ourselves to noting the unassailable $8:7$ ratio between the diameters of the two circles. This line is the length of the chord that, developing geometrically, generates the Square of the Earth. The length of this chord and its reflection with respect to the Cardo establishes the position of the vertices of a rectangle having the exact proportions of the crossing of the transept of this abbey where the respective four large columns are built. Thus, the two sides determine the proportion between the width of the nave and the length of the transept. What symbolic meaning do these two numbers have? The Pythagoreans called the Numerical Entity, identified modernly with the number seven, by particular terms expressing its main qualities: He who brings to completion, opportune moment, Divine Presence, Victory. The number 7 is considered, since the most remote antiquity, as the sacred number par excellence: it symbolizes the complete expression of an action, the fullness of a dynamic cycle. It communicates the complete actualization of the wise Divine act that orders chaos. The Seven symbolizes ascent, the source of every change, the completed cycle, the perfection of human nature. All this indicates a precise path of perfection that always happens by degrees, a mystical ladder that transports the ascetic into ever higher octaves. But seven are also the ancient cosmic Guardians who defend the path of approach to the center from the intrusion of fools and desecrators. Seven guardians, one for each concentric circle, as seven are the planets of classical Astrology that surround the earth. The number eight was instead called: Stability, Glory, Eternity. The number 8 is the first and only cubic number of the decade and as such symbolizes the passage to another dimension. It manifests the perfection of what the Seven had prepared and completely expressed: the seven notes that form and complete the musical scale plus the octave, that is, the first note of a higher octave. The Eight manifests itself with the figure of the octagon, a form that symbolically places itself between the square and the circle (representing earth and sky) thus declaring itself as the mediator between these two realities. The octagon evokes the new world, declares itself as the passage to reach it. Christian baptismal fonts often have an octagonal shape at the base or rise on a round structure with eight pillars, since, as Saint Ambrose attests, [...] it was right that the hall of the Sacred Baptistery should have eight sides, because true salvation was granted to peoples when, at the dawn of the eighth day, Christ rose from the dead. The $\frac{8}{7}$ module brings, at the human level, the complete expression of a dynamic ascent toward divinity, a path in which one must know, face and win spiritual battles until union with the divine through the Mystery of the eighth day. Keeping well in mind that this particular sacred architecture, inspired by the teachings of Saint Bernard, bases its constructive perfection and aesthetic harmony on profound numerical-geometric symbolisms (as we have analyzed), golden ratios between the parts.