Book excerpt: The postal system of the Byzantine Empire, the cursus publicus or dromos, was a pony express-style system of routes and relays, capable of moving messages at up to 100 miles (160 km) per day. In this fascinating book, Jason Fossella describes the infrastructure, operations, and administration of the dromos. Drawing on sources as varied as papyri, seals, inscriptions, and ancient histories, the author examines how the dromos was integrated into Byzantine society and influenced the development of Byzantine diplomacy, ceremony, and religion, demonstrating that it played a key role in the development of Byzantine imperial power.