The purpose of this workshop is to introduce new findings on two important music theories from ancient China and Greece. It focuses on the monochord as a scientific apparatus that aided the development of theories attributed to Guanzi in the seventh century BCE and Pythagoras in the sixth century BCE. These techniques were both musically intuitive and mathematically sound for creating chromatic scales. Developed thousands of years ago, these theories constitute the core of modern music theory and still invluence aspects of music education, human cognition, social relationships, and long histories of civilization. This workshop will contribute new perspectives on ancient music theory and related issues across disciplines such as classics, philosophy, mathematics, history, archaeology, anthropology, music theory, music performance, and music education, and also facilitate the development of new tools and methods for research and teaching.