The faith of Mexican Americans in the American Southwest in the nineteenth century had the inward convictions and outward Christian stamp of the generations of Spanish and mestizo (mixed-blood) missionaries and laity who brought Christianity to North America. But Mexican Americans were also heirs of a variety of Native American beliefs and practices that were as ancient and as deeply rooted as those introduced by the Europeans. These newcomers had not simply offered the gift of Christian salvation to los naturales (the indigenous peoples); they arrived on these shores as political and economic, as well as spiritual, conquerors with the expressed intention of ruling over the Indians, taking their lands and their labor, and replacing their faith traditions. But try as they might, the newcomers were unable to extirpate all the native traditions, and some settled on “baptizing” Indian religious expressions or simply learning to live with them. While not all the missionaries agreed on what indigenous rituals they could tolerate or accommodate, conversion of the native peoples involved an extensive process of give-and-take; and in the end, Spanish European Christianity was transformed in the New World. Still, the Catholic faith gradually became the core faith of the indigenous peoples of Central Mexico, facilitated by traditions amenable to Indian religiosity such as the effi cacy of grace through sacramental symbols and rituals, the intercession of the saints, a communal salvation (the communion of saints), and an incarnational theology that saw the presence of God in a truly human and cultural context.