Medieval warfare was dominated by the attack and defence of fortified places, and siege methods and technology developed alongside improvements in defences. This book uses both original historical sources and evidence from archaeology to analyse this relationship as part of a comprehensive view of the whole subject, tracing links across three continents. It considers the most important questions raised by siege warfare: who designed, built and operated siege equipment? How did medieval commanders gain their knowledge? What were the roles of theoretical texts and the developing science of siege warfare? How did nomadic peoples learn to conduct sieges? How far did castles and town walls serve a military purpose, and how far did they act as symbols of lordship? The volume begins with the replacement of the western Roman empire by barbarian successor states, but also examines the development of the Byzantine Empire, the Muslim Caliphate and its successors, and the links with China, through to the early thirteenth century. The companion volume, A History of the Late Medieval Siege, continues the story to 1500.