To Bach, the Circle of Fifths was the language of the universe. Similar to the constellations used to understand the sky, the Circle of Fifths is a visualization device to understand the fundamental concepts of key signatures, which are the foundation for music. The Circle of Fifths is a guide for writing music because its structure helps compose and harmonize melodies, build chords, and move to different keys within a composition. The Octave is the most significant key signature because it completes the circle of fifths. The Octave, if in perfect tune will create an overtone, which is a tune unable to be created on its own. The movement through the Circle of Fifths led to a contemplation described by Pythagoras as "Music of the Spheres" or meeting between heaven and earth, between spiritual and material realms. The Well Tempered Building uses the Circle of Fifths as the underlying geometry for the foundation of the conservatory. Proportions from the Circle of Fifths, including the Octave, shaped the conservatory making the musicians, audience, sound, light, water and air tuned to each other. / Master of Architecture

Obwohl die genaue Kenntnis der Tonartenverwandtschaften für die Modulationslehre wesentlich ist, verschwand dieses Thema im 19. Jahrhunderts allmählich aus den Harmonielehren, bis sich die Messung von Verwandtschaftsgraden in der Musiklehre des 20. Jahrhunderts fast nur noch auf das Kriterium des Quintenzirkels beschränkte. Der Blick zurück ins 18. und 19. Jahrhundert ergibt ein weitaus differenzierteres Bild in der Beurteilung von Verwandtschaftsgraden. Zwei Tendenzen lassen sich feststellen: Erstens führt die Orientierung der Theorie an der kompositorischen Praxis zu einer stetig sich erweiternden Legitimierung entfernter Tonarten als nahe Verwandte. Zweitens ist bis Jacob Gottfried Weber eine Zunahme an Verwandtschaftskriterien zu konstatieren, deren Differenzierung in der Folgezeit zugunsten einer wachsenden Integration fremder Tonarten wieder zurückgeht. Differenzierung der Kriterien und Integration von Tonarten verhalten sich gegenläufig zueinander. / Despite the intrinsic significance of key relationships on the conceptualization of modulation, this topic gradually disappeared from treatises in the nineteenth century until the measurement of key relationships was eventually restricted almost exclusively to the circle of the fifths in twentieth-century teachings. A glance back at the eighteenth and nineteenth centuries reveals a far more differentiated picture regarding the judgement of key relationships. Two tendencies can be discerned: first, the orientation of theory on compositional practice led to a continually expanding legitimization of distantly related keys as more closely related ones; second, until Jacob Gottfried Weber one can detect an increase in relational criteria whose differentiation in the following years declines again in favor of an expanding integration of foreign keys. Thus differentiation of criteria and integration of keys exist in opposition to one another.