During the fifth and sixth centuries A.D. there arose on the Euphrates frontier, between the empires of Rome and Iran, a city girded with glittering gypsum walls. Within these walls stood a great church, a shrine for the relics of Saint Sergius, who was martyred there, at Rusafa, in the early fourth century. Round about stretched the "Barbarian Plain," inhabited by Arab tribes in unstable alliance with Rome. When these people became Christian, they took the soldier-martyr Sergius to their hearts and made of him a rider-saint in their own image. Emperors of both Rome and Iran, as well as princes of the Arabs, courted the martyr's favor. Pilgrims entreated him to heal their afflictions. Merchants traded, and treaties were negotiated under his protection.. "In this study of the growth of a martyr cult in late antiquity, Elizabeth Key Fowden draws on literary accounts, inscriptions, archaeology, images, and the landscape itself to construct a many-faceted picture of the role of religion in a frontier society - as much in the lives of the ordinary faithful as in the strategic calculations of hostile empires.