This dissertation highlights the decisive role played by a group of Black Catholics priests and lay people on Rio's urban periphery whose religiously-informed activism led to the 2001 state law in Rio de Janeiro that mandated racial affirmative action in the state's public universities. Their story begins with the struggle for democracy and liberation, spearheaded by Bishops' supportive of liberation theology, which developed into an organization of Black clergy who demanded adequate representation within the church. As part of raising Black consciousness, they pioneered a reform of the Catholic liturgy through "Afro Masses," informed by a theology of inculturation, that sought to teach Catholics to respect Africa, its cultures, and its descendents. Starting in 1992, they began to target higher education by pioneering a free college exam prep program for "Blacks and the poor" which, gaining a mass following after 1997, contributed to the 2001 Rio victory for affirmative action; after this 'conquest,' the rest is history some have suggested. this dissertation will argue for the need to understand liberationist Catholicism as a journey in which the pursuit of spiritual, political, personal and collective liberation contributed decisively to the formation of a secular but nonetheless Catholic political culture. This liberationist Catholic political culture reaches far beyond the church and includes many who no longer explicitly identify publicly as Catholic in their secular roles. While the 1984 Vatican rebuke led some to leave the priesthood, activist religious Catholics did not retreat from public sphere but sought instead to make common cause with secular organizations ranging from trade unions, black movements, NGOs, and political parties that were often led by Catholics. The broader hypothesis of the thesis is that a "liberationist" universalism, derived from Catholic roots, is central to understanding why the PT surprised focusing on affirmative action policy.