A study of the religious roles, public and private, of late-medieval holy women. This is part of the introduction to the Yale Guide to Medieval Holy Women in the Christian Tradition: Twelfth through Fifteenth Centuries, which Yale University Press has commissioned Dr. Rosalynn Voaden and myself to produce. The reasons why the medieval church refused to ordain women for the priesthood are investigated, in comparison and contrast with the roles medieval women were allowed and/or sought for themselves, and the degrees of success they had in pursuing their spiritual vocations. The first part of this study includes material from the Church Fathers through the major schoolmen of the high Middle Ages, particularly Saints Thomas Aquinas and Bonaventure, Henry of Ghent, and Duns Scotus. These later figures, all of whom were associated with the University of Paris, produced substantive arguments against women priests. They and their successors also attacked the ways in which certain heretical movements (including Cathars, Albigensians and Lollards) were willing to allow women some priestly functions. However, the extent to which such groups did promote such a startling innovation has been exaggerated. The impedimentum sexus — the impediment or bar of female sex or 'gender' — generally functioned to prohibit women from the 'public' offices (preaching, administering the sacraments, etc. ) which were constitutive of priesthood. The second part of this study moves from scholastic theory to the actual lives and works of holy women, including Angela of Foligno, Beatrice of Nazareth, Bridget of Sweden, Catherine of Siena, Elisabeth of Schônau, Juliana of Mont-Cornillon, Margaret of Ypres, Marie d'Oignies, and Mechthild of Magdeburg. Taking female 'ministry' in a wider, 'unofficial' sense, a variety of roles may be seen as available to women. They could serve as abbesses and counselors to nuns and other religious women; gain the release of souls from purgatory; 'privately' advise kings and high-ranking Churchmen (including bishops and even popes); admonish errant Christians (including wicked priests); put questions to Christ and the saints on behalf of confused clerics; lobby the Church to accept new rituals and practices — and above all else, have visions, dream dreams, and prophesy. Divine inspiration was no respecter of the impedimentum sexus: it authorized certain holy women to provide the Church with fresh theological insights. However, running counter to the obligation to 'make public' the divine secrets thus revealed was a discourse of keeping secrets to one self. No matter how much work they did for the health, spiritual and physical, of others, through their visions and meditations medieval holy women essentially worked for themselves. Far from being condemned as selfishness, such activity was seen as the very abnegation of the self, a process whereby wayward human desire was brought into conformity with the divine will. In the secret spaces of their hearts, medieval holy women found rooms of their own. And this may be seen as the ultimate triumph of the private over the public.