One of the most famous rulers in Chinese history, the Yongle emperor (r. 1402–24) gained renown for constructing Beijing's magnificent Forbidden City, directing ambitious naval expeditions, and creating the world's largest encyclopedia. What the Emperor Built is the first book-length study devoted to the architectural projects of a single Chinese emperor. Focusing on the imperial palaces in Beijing, a Daoist architectural complex on Mount Wudang, and a Buddhist temple on the Sino-Tibetan frontier, Aurelia Campbell demonstrates how the siting, design, and use of Yongle's palaces and temples helped cement his authority and legitimize his usurpation of power. Campbell offers insight into Yongle's sense of empire―from the far-flung locations in which he built, to the distant regions from which he extracted construction materials, and to the use of tens of thousands of craftsmen and other laborers. Through his constructions, Yongle connected himself to the divine, interacted with his subjects, and extended imperial influence across space and time. Spanning issues of architectural design and construction technologies, this deft analysis reveals remarkable advancements in timber-frame construction and implements an art-historical approach to examine patronage, audience, and reception, situating the buildings within their larger historical and religious contexts.