This book explores how political power was exerted and family identity expressed in the context of reconstruction of the noble families of the medieval duchies of Gaeta, Amalfi and Naples. Localised forms of power, and the impact of the Norman conquest on southern Italy, are assessed by means of a remarkable collection of charters preserved in the Codex diplomaticus Cajetanus. The duchy of Gaeta, like its neighbours, was ruled as a private family business. An integral part of its ruling family’s power was its monopolisation of parts of the duchy’s economy, the use of members of the clan to rule local centres. When the family broke up, the duchy fell to outside predators. The three duchies reacted in different ways to the Normans. Gaeta flourished commercially in the twelfth century, and its unique political response to contacts with the cities of northern Italy (especially Genoa) forms the final part of this study.