1 The Pythagorean Theory of Harmony in Architecture and Music from Antiquity to the Middle Ages

The close affinity between music and architecture has been passed down for nearly three thousand years by the Chinese, the Egyptian, and in particular the Greek history of culture and philosophy. According to this ancient understanding, music and architecture are based in equal measure on order structures that we can express in the form of numeric relationships and which find their particular exemplification in the theory of musical harmony and the theory of architectural proportion.

In antiquity, the Pythagorean theory of harmony was considered the universal standard of musical composition and, in derivation from this, also the standard of architectural design – be it, for example, in the form of the arrangement of columns, the dimensional ratio of the ground plan of a building, or the organization of facades. In the Platonic dialogue Timaeus, which deals with the creation of the world soul and the cosmic order in terms of a harmony of the celestial spheres, the Pythagorean relationships of the whole to its parts is explained. According to the Pythagoreans, number harmonies manifest themselves both in the constitution of the entire cosmos as well as in the structure of the human soul. The earliest application of the Pythagorean theory of harmony in architecture was handed down in Vitruvius’s treatise De architectura libri decem from the first century B.C., in which it is said to serve the successful creation of the proportions of crafted objects. Vitruvius called for a knowledge of music to be part of an architect’s education.

In the following centuries, the numeric aesthetics based on the Pythagorean concept of harmony was – in different variations and adaptations – definitive for the theory and practice of music and architecture. In the Middle Ages, the ancient cosmic theory of harmony was elevated with Christian symbols and associated with special construction methods (for instance, the golden cut and Fibonacci numbers). These developments in the relationship between music and architecture were again taken up theoretically in tracts by Augustinus or Boethius, for example, and were used both in Christian cult buildings, such as medieval minsters and Gothic cathedrals, and in the famous lodge book by Villard de Honnecourt of the early thirteenth century.

There is a special relationship in terms of architectural and musical harmony between the Florentine cathedral Santa Maria del Fiore and Guillaume Dufay’s motet Nuper rosarum flores from 1436, which was performed on the occasion of its consecration. Analogies can be identified between the numeric structure of the motet and the proportional dimensions of the cathedral.