This book is an exploration of the nature of power in early medieval Wales. Wendy Davies examines the distribution of power, territorial and social, and traces the ways in which contemporaries defined this fundamental concept. She confronts challenging questions relating to definitions and consequences of military control, alien settlement, landownership, and political domination. Professor Davies analyses the impact and nature of English, Irish, and Viking contacts with the Welsh, and argues their significance for the long-term development of Wales. This is a stimulating and scholarly study by one of the foremost historians of the Celtic world.