Among the various aspects of the operation of canon law in medieval England, the history of the Anglo-Norman school of canonists which flourished in the late twelfth and the early thirteenth centuries remains largely unexplored. Modern historians have frequently emphasized, to be sure, the eager interest which English churchmen of the twelfth century took in problems and issues of canon law; and it can now be considered an established fact that the English Church throughout this period was well abreast of the developments which everywhere resulted from the growing centralization of ecclesiastical procedure, from the work of Gratian and his school, and from the ever-increasing number of authoritative responses and appellate decisions rendered by the popes in their decretal letters. The importance of the system of delegate jurisdiction in the cases referred back by Rome to the country of origin has been noted, and so has the conspicuous number of twelfth-century English collections of decretals, which testifies to a particular zeal and tradition, among Anglo-Norman canonists, in supplementing Gratian's work by records of the new papal law. The problem, also, of the influence exercised by Roman and canon law on the early development of the Common Law is being discussed with growing interest among students of English legal and constitutional history.