This seminar examines the history of Western musical thought in antiquity and the medieval period, with attention to the parallels between developments in music theorizing and the other sciences. Ancient Greek approaches to musical thought are well attested, and an investigation of Pythagorean doctrines of music and mathematics begins the course, along with the treatise of Aristoxenus, a student of Aristotle who radically advanced his teacher’s tenets. In connection with the Vorlesung, the seminar addresses medieval chant, focusing on how authors of the time described its modes and notation, as well as the emergence of polyphony. Developments of the late medieval period include metrical theories to account for compositions‘ rhythmic complexity, and adaptations of philosophical and scientific concepts taught in early universities to help theorize musical practice of the day.