This is the first full scholarly study of the relationship between native secular law and the Church in medieval Wales. The interaction was close, despite Archbishop Pecham's condemnation of native law as the work of the devil. Huw Pryce assesses the influence of the Church on Welsh law, examining the participation of churchmen in the composition of lawbooks and the administration of legal processes and analysing ecclesiastical criticism of native customs, notably those concerning marriage. He also considers the extent to which Welsh law defended the authority and possessions of the Church, focusing in particular on the status of clerics and on rights of sanctuary and lordship. The book throws revealing new light on both secular law and the Church in Wales in the twelfth and thirteenth centuries. As a study of the impact of ecclesiastical reform on a society perceived by some contemporaries as barbarian and immoral, this scholarly and lucid account makes an important contribution to medieval history.