Book excerpt: This pioneering study examines a pivotal period in the history of Europe and the Near East. Spanning the ancient and medieval worlds, it investigates the shared ideal of sacred kingship that emerged in the late Roman and Persian empires. Bridging the traditional divide between classical and Iranian history, this book brings to life the dazzling courts of two global powers that deeply affected the cultures of medieval Europe, Byzantium, Islam, South Asia, and China.