Study of the Norman World's borders, frontiers, and boundaries in Europe, shedding fresh light on their nature and extent. The Normans exerted great influence across Christendom and beyond in the eleventh and twelfth centuries. Figures like William the Conqueror and Robert Guiscard subdued vast territories, their feats recorded for posterity by chroniclers such as Orderic Vitalis and Geoffrey Malaterra. Through travel and conquest, the Normans encountered, created, and conceptualised many borders, with the areas of Europe that they ruled and most affected often being grouped together as the "Norman World". This volume examines the nature, forms, and function of borders in and around this "Norman World", looking at Normandy, the British-Irish Isles, and Southern Italy. Three sections frame the collection. The first concerns physical features, from broad frontier expanses, to rivers and walls that were both literally and metaphorically lines of division. The second shows how borders were established, contested, and negotiated between the papacy and lay rulers and senior churchmen. Finally, the third highlights the utility of conceptual frontiers for both medieval authors and modern historians. Among the subjects covered are Archbishop Anselm's travels across Christendom; the portrayal of borders in the writings of William of Jumièges, Orderic Vitalis, and Gerald of Wales; and the limits of Norman seigneurial and papal power at the edges of Europe. Overall, the essays demonstrate the role that the manipulation of borders played in the creation of the "Norman World", and address what these borders did and whom they benefited.