There is a dearth of Western scholarly research on ancient Chinese music. Unlike the trajectory of Western music—where the Catholic Church facilitated a linear, centralized, and well-chronicled musicological evolution—ancient Chinese music history is fragmented and incomplete. Dynastic cycles often led to hostile transitions of power and the destruction of the cultural vestiges from the preceding fallen dynasty. As a consequence, the elegant Yanyue twenty-eight-mode system of the Tang dynasty is scarcely known or understood in the West. The musicological history of the Yanyue modal system is disjunct and imprecise. This document will reconstruct the theoretical architecture of the Yanyue twenty-eight modes and unveil them for a Western audience. The Sui and Tang dynasties (581-907) reflect an extended phase of political stability and economic prosperity. The Tang dynasty in particular was a period of renaissance and artistic cultivation. It embraced migration and the blending of disparate cultural traditions. This document will reveal the Yanyue twenty-eight modes to be not merely a musicological artifact, but a sonically ornate and remarkably diverse tonal system whose structural organization reflects the heterogeneity of Tang itself and colors our image of life in ancient China.