The paper addresses the issue of the structure and extent of jurisdiction of the Catholic Church courts operating in medieval England prior to the occurrence of the Anglican schism. The Norman Conquest is placed in the historical period considered as a watershed for the development of English judicial institutions. It is from this historical period that the formal distinction between civil tribunals and ecclesiastical tribunals (not foreseen in the Anglo-Saxon era) takes shape and a hierarchical system of articulated and rigidly structured ecclesiastical tribunals that will be exercised, until the sixteenth century, a jurisdiction much wider than that exercised by the same courts on the Continent, extending ratione spiritualibus also in temporalibus rebus, investing both disputes between clergy and lay people. This state of affairs has led the canon law applied by ecclesiastical tribunals to be an undisputed protagonist in the formation of individual institutions that characterize the current Anglo-Saxon law and, more generally, in the development of the entire English legal system.