This project explores the manner in which the scholastic notions of Neoplatonic "music of the spheres" relate to the philosophical and scientific paradigms that emerged during the thirteenth and fourteenth centuries. It thus casts light on the gradual assimilation of Aristotelian natural philosophy and of Greco-Arabic astronomy into Latin musical cosmology and philosophy and on the impact that upstart scientific doctrines had on the philosophical reworking of this Neoplatonic concept. I will particularly focus on musical cosmology as manifest in the works of the great 14th-century mathematician, Nicole Oresme, and investigate the manner in which his notions of a cosmic music build upon his own kinematics of circular motion, rigorous mathematical models, and aesthetic concepts. I will concentrate on: (1) the dynamic relationship between Oresme's taxonomy of sounds and their graphical representation as conditions for infinitely variable degrees of "beauty"; (2) his notion of "sensible" and "insensible" sound a s parameters differentiating between "human" and "divine" music; (3) the degree to which Oresme's writings present a relatively unified corpus of acoustic and aesthetic theories of sound; and (4) the manner in which these theories become mathematically integrated in a dynamic though not precisely codified polyphony manifest in an Aristotelian-Ptolemaic cosmos. Furthermore, I will situate Oresme's musical cosmology in the larger scientific and intellectual trends of the fourteenth century, particularly as manifest in the intellectual circles of Oxford and Paris. Given the extent to which Oresme's thought situates him at the crossroads of quadrivial speculation in the fourteenth century, and connects him with some of the most significant musicologists, historians of science, and scholars of medieval intellectual history alike.