This book provides an introduction to the history of medieval Wales, with particular emphasis on political developments. It traces the growth of Welsh princely power, and the invasion and settlement of Welsh territories by Norman adventurers which resulted in the creation of the marcher lordships and the steady erosion of Welsh princely authority in the south. The subsequent development of a powerful Welsh state under the leadership of the princes of Gwynedd was checked by Edward I in 1277, and thereafter the principality was deliberately overrun and destroyed: the Edwardian castles are symbols of conquest. Despite valiant attempts by local leaders in the thirteenth century, and by a national leader Owain Glyn Dwr early in the fifteenth, the English domination of Wales persisted, even beyond the advent of the Tudor dynasty. This is the first comprehensive short textbook on medieval Wales to be written for school and university students. It will also attract anyone with a general interest in Celtic studies or in the centuries which played such a formative role in the development of the Welsh national character.