In late July 1263 a public disputation was convened by King James I of Aragon, pitting Friar Paul Christian against the distinguished rabbi of Gerona, Moses ben Nahman. Organized by leading figures in the Dominican Order to give Friar Paul an opportunity to test his innovative missionizing argumentation against a worthy opponent, the spectacle in Barcelona was colorful, impressive, surely somewhat frightening to the Jews, and ultimately indecisive...