The story of King Alfonso VIII of Castile’s affair with a Jewess of Toledo is perhaps the most famous medieval account of love between a Christian and a Jew. This article begins with the story’s first appearance toward the end of the thirteenth century and traces its expansion across several hundred years, in order to describe the roles played by figures of Judaism (and of women) in enacting and representing conflict within Christian politics. Once embedded in Castilian political theology, the Jewess reveals a good deal about how and why charges of Jew-love and Judaizing were deployed in late medieval conflicts over new forms of monarchical power, centralizing government, and administration. The article concludes with a focus on the Jewess’ role in both legitimating and criticizing a particularly important practice: the increasing royal delegation of administrative power to one favored minister (privado). By placing the Jewess at the center of debate over this practice, the article demonstrates how she simultaneously contributed to and reflected a transformation of the possibilities for Christian politics in Castile and for Jewish life in Sefarad.