During the antebellum period, the Roman Catholic church in the United States experienced phenomenal growth, becoming by 1860 the single largest Christian denomination in America. Simultaneously, Catholics, like other Americans, engaged in an internal migration that forced the church to spread westward. With these changes came substantial challenges for the church, including the need for institutional development and increased personnel to minister to this growing and mobile population. Not only did members need churches in which to receive the sacraments, and priests to administer them, but also schools and orphanages where Catholic parents could raise their children in the faith. While many historians have examined these developments in the context of new parishes and dioceses, staffed by priests and bishops, few have considered another event of equal significance in the development of American Catholicism in the antebellum era: the emergence and growing importance of communities of women religious.

Especially in areas underrepresented by priests, sisters served the growing Catholic population in various ways, from teaching and religious instruction to nursing and social work. In particular, the schools these women founded, administered, and taught in predated and foreshadowed the parochial school system and provided the only available Catholic education in many areas prior to the Civil War. Through this work, sisters became important representatives of the Catholic church, often the primary point of contact between the institutional church and the laity. But these women did not limit their efforts to Catholics; they also ministered to the Protestant world. Their numerous and varied schools welcomed both Catholic and Protestant students, thereby giving children of different religions an opportunity to coexist and interact with one another. Likewise, these sisters provided visible, positive images of Catholicism to their students, to their students pare