Beginning in Paris in the year 1290, Jews were accused of abusing Christ by desecrating the eucharist—the manifestation of Christ's body in the communion service. Over the next two centuries this tale of desecration spread throughout Europe and led to violent anti-Jewish activity in areas from Catalonia to Bohemia, particularly in some German-speaking regions, where at times it produced regionwide massacres and "cleansings." Drawing on sources ranging from religious tales and poems to Jews' confessions made under torture, Miri Rubin explores the frightening power of one of the most persistent anti-Jewish stories of the Middle Ages and the violence that it bred. She looks not just at the occasions on which massacres occurred but also at those times when the story failed to set off violence. She investigates as well the ways these tales were commemorated in rituals, altarpieces, and legends and were enshrined in local traditions. In exploring the character, nature, development, and eventual decay of this fantasy of host desecration, Rubin presents a vivid picture of the mental world of late medieval Europe and of the culture of anti-Judaism.