The recent accession to the Vatican Archives of registers of the Sacred Penitentiary, a category of business which remained closed when the general records of the papacy were opened to scholarly research at large in 1881, is an important development. It has especially exciting implications for late medieval Irish history The availability of the Penitentiary material will greatly facilitate an undertaking which is of prime importance but for which the sources are otherwise scanty the study of religious sentiment in Ireland in the period from about the second decade of the fifteenth century, when these registers begin, to the Reformation. This is an aspect of ecclesiastical history to which the legalistic and contentious documents of the beneficiary deposits, the principal point of contact between Ireland and the papacy in the middle ages — though immensely valuable in their own right — do not readily lend themselves.