The birkat haminim is a prayer in the weekday Jewish liturgy for the removal of those categories of humans who prevent messianic redemption. Its earliest known texts, themselves medieval, curse apostates (to Christianity), sectarians, Christians, enemies of Israel, and the insolent empire. Jewish sources place the origin of the prayer in the late first century, in response to an ambiguous group challenging rabbinic authority. Some Church Fathers knew of the prayer and complained that Jews were cursing Christians. The origins of this prayer, were they knowable, should illuminate early Christian-Jewish relations. However, the story of the prayer continues until today. Drawing on the shifting liturgical texts and polemics and apologetics surrounding the prayer, Langer traces the transformation of the birkat haminim from what functioned without question in the medieval world as a Jewish curse of Christians, through its early modern censorship by Christians, to its modern transformation into a generalized petition that God remove abstract evil. Christian censorship itself had opened the door to this transformation by destabilizing the prayer’s language. The true transformations in its meaning, however, accompanied Jewish integration into Western culture and consequent changes in mindset. Thus, even when censors ceased to concern themselves with Jewish texts, changes to the text only enhanced the trajectories already in place. The prayer both lost its function as a curse and its references to any specific categories of living human beings.