This book examines the development of English colonial society in the eastern coastal area of Ireland now known as county Louth, in the period 1170–1330. At its heart is the story of two relationships: that between settler and native in Louth, and that between the settlers and England. An important part of the story is the comparison with parts of Britain which witnessed similar English colonization. Fifty years before the arrival of the English, Louth was incorporated into the Irish kingdom of Airgialla, experiencing rapid change in the political and ecclesiastical spheres under its dynamic ruler Donnchad Ua Cerbaill. The impact of this legacy on English settlement is given due prominence. The book also explores the reasons why well-to-do members of local society in the West Midlands of England in the reigns of Henry II and his sons were prepared to become involved in the Irish adventure.