ABSTRACT
This chapter deals with a particular mode of thought embedded in both Ancient and Medieval music theory: a mathematical bent stemming from the idea that Music, based on proportional relationships which embody Number, is an audible symbol of a God-given ontological order. These were the ones who attempted to find a lesser common denominator for musical intervals, irrespective of rational proportions; who conceived instruments meant for acoustical research, including the monochord adopted by the followers of Pythagoras; and who ended up by creating and developing Greek musical notation. It would be impossible not to notice that the basic rhythmic proportions correspond, melodically, to the unison, the octave, the twelfth, the fifth and the fourth; rhythmics, metrics and harmonics were completely congruent from a mathematical point of view.
