On November 22, 1981, thousands of laypeople, along with bishops, priests, and theologians, gathered in Recife to celebrate the Eucharist. Offered during a military dictatorship in a period of popular insurgency, the Quilombos Mass mourned the death of millions in the African slave trade, sought pardon for the Church's past sins, and celebrated the resistance of Blacks in Brazil and beyond its borders. The acclaimed Black Brazilian pop star and activist Milton de Nascimento collaborated with an activist poet and three bishops to produce a multimedia performance; in the spirit of liberation theology, it was marked by striking visuals, dance, music, and the invocation of the sacred. This article draws on reportage, speeches and correspondence, military court and intelligence records, published interviews, and the author's interview with one of its composers. It offers a close textual analysis, with attention to Catholic theological debates, as well as an analysis of the performance itself, drawn from video recordings and bringing attention to aspects neglected by most commentators, who refer only to the album, as it was finally produced. Initially stifled by the Vatican, Milton's masterpiece, issued as an album on vinyl and performed in paid concerts, became a powerful cultural reference for activists, serving as a touchstone for a strategic alliance between Black activists and the liberationist Church.