This article discusses a number of the dominant features of late nineteenth- and early twentieth-century Indian Catholicism on the Rosebud Reservation, focusing primarily on the Sicangu's responses to the significant differences between their traditional religious customs and the beliefs, rituals, and requirements of Catholicism. It first examines several of the basic assumptions that informed the Sicangu's reception, interpretation, and practice of the "prayer" of the "Sina Sapa", or Blackrobes (Jesuits), drawing upon their statements regarding the sacraments and other church practices to illustrate these processes. It then describes selected strategies, including various modes of resistance and adaptation, that the Sicangu employed to cope with the Catholic requirement of ecclesial exclusivity--a policy that, as will be shown, stood in direct opposition to the fundamental Lakota tenet of the plentitude of sacred power. Finally, this essay considers ways in which Sicangu and other Sioux Catholics refashioned selected aspects of their annual religious congress to reflect elements of traditional Lakota religious beliefs and practices.