This study of the area around St Saviour's Abbey (Alto Lazio/Tuscia, Viterbo, southern Etruria, Italy) is based on multidisciplinary research methods which employ analyses of documents, surveys, aerial archaeology, and modern computer technologies to determine the connection between archaeological and documentary data. The abbey, according to tradition, was founded by the Lombard King Ratchis. The main objective of this volume is to determine archaeological evidence that may be linked to the many settlements reported in the abbey's extant literary and MSS resources.