The rapid increase in monastic acquisition of parish churches in the twelfth century reflected a number of trends, both temporal and spiritual, in the Christian society of western Europe. It was an expression of the laity's continuing devotion to the monastic ideal, now reinforced by the foundation and spread of new religious orders, and it was in part a consequence of the redefinition of relations between the laity and the clergy following in the wake of the Gregorian Reform. More than that, however, it raised within the Church questions as to the proper relationship between the monastic clergy and the pastoral and juridical structure of the Church. To understand the phenomenon, therefore, it is necessary to examine the motives of donors of parish churches and those of the religious who received them, to bear in mind the climate of respectable opinion (both lay and-ecclesiastical) which came increasingly to deny possession of parish churches to the laity and yet could countenance their passage into the hands of religious houses, and to consider the repercussions of widespread monastic acquisition of churches in the Church at large. This article is concerned in particular to re-examine the means by which monasteries obtained grants of churches, viewed against the background of the Church's assault on lay ownership of churches and tithes, and to reconsider the evolution of the vicarage system, as the ecclesiastical authorities strove to accommodate within the mission of the reformed Church monastic efforts to exploit the churches in their possession.