Decentralisation and outsourcing are not new to British history. In medieval England the practical limitations of the reach of the Crown forced the king and the government to entrust some autonomy and legal powers to its regional aristocratic rulers. The Norman and Plantagenet kings relied upon these nobles for the protection of the dangerous frontiers of the realm. In Wales, as in Ireland, the smaller size and military inferiority of the often divided neighbouring states encouraged conquest, with the seized lands enhancing the power of the aggressive English lords’ domains. The great lords of the Welsh Marches were granted ever greater authority to the point where they believed they ruled like kings. They intermarried, schemed for extra lands and snatched power in a complex and often violent political process. Due to their huge resources and unparalleled military experience, they soon came to overawe weak kings and dominate national events. The strength of the Marcher Lords would come to the fore at various points throughout history, characterised by notorious figures such as Simon de Montfort, Roger Mortimer and Edward IV. Timothy Venning showcases the mentality of the Lords of the Marches, and reveals the dramatic careers of those who prospered from their loyalty to the king, to those whose power was gained by treachery. This is their story, from the Norman Conquest to the beginnings of the Tudor dynasty.