“Who has stolen the loaves from the oven? / The Jewish dogs, the Jewish dogs” (3). This Chilean children’s refrain from the memoir of the writer Marjorie Agosín encapsulates the “theft of the host” accusation that originated in the thirteenth century. It provides Stow with the foundational metaphor for this book, part meditation on the persistence of anti-Judaism within Catholic thought, and part historical detective story. The book is structured in concentric layers so that its introduction and final chapters form the outermost shell, its next tier comprises the second and the penultimate chapter, while its core is at the center.

The medieval core of the book turns on events that occurred during the reign of the French King Philip II Augustus of France (1179–1223). These include an alleged case of ritual murder by French Jews of Richard of Pontoise in 1179, the expulsion of French Jews in 1182, their eventual recall in 1198, and Philip’s edict restricting moneylending by Jews in 1206. Philip, Stow argues, was raised hearing that Jews murdered a Christian every year in order to ingest the blood as a gruesome anti-Eucharist celebration. (This comes a decade before any formal charge of that sort was ever leveled against Jews.) News of the alleged French victim, Richard, served as confirmation to Philip that the stories were true, prompting him to act against the Jews in his realm; only “avarice” (reasons of state) caused him to recall them later. Stow bolsters his case with a radical rereading of a set of Hebrew texts, long believed to reflect events occurring during the reign of Philip’s father, Louis VII. Instead of reflecting historically on the events surrounding the Blois episode of 1171, in which Louis VII’s brother-in-law Count Theobald ordered some thirty Jews burned alive on false charges of ritual murder (no victim was ever found), Stow reads the letters as an ironic inversion of the events during Philip’s reign. This rereading is sure to prompt further discussion of the text and of Stow’s interpretation of the events.

But the medieval crux is only the first step in Stow’s trajectory. These materials were mediated and edited in crucial ways by the seventeenth-century Bollandists, Jesuits of Leuven and Antwerp who sifted medieval texts to substantiate or reject claims to sainthood in their monumental collection Acta Sanctorum. Stow’s Bollandists see the victims of Jewish ritual murders as surrogates for the Eucharist, which Jews were always trying to violate.

Stow notes with concern that while ritual murder and blood libel charges preserved in hagiographies had begun to subside by the mid-nineteenth century, such charges were revived in the late nineteenth and early twentieth centuries. Roman Jesuits supported the myth, while, outside Rome, Jesuit Bollandists repudiated it. Chief among the latter were Hippolyte Delehaye and François Halkin, and the Jesuit scholar Peter Browe. The supporters of the myth tended to be Catholic integralists who were opposed to any concessions in the face of modernity, while those who repudiated it tended to be supporters of freer modern critical scholarship and thought. Stow traces a similar pattern in France and Germany as well.

The three layers of narrative, each fully realized and set within the context of their time, are united by their concern for the purity of the Christian polity. The title image derives from Jesus’s statement in Matthew 15:26 that it is not fitting that bread intended for the children be thrown to the dogs. In its original context “children” were the Jews and the “dogs” were the heathens, but Christian exegetes noted that things had become inverted: they had become the favored children and Jews had become the dogs, constantly trying to violate the purity of the bread. Thus the image is also concerned with the Christian doctrine of supersession. A second metaphor concerns the loaf of bread, standing for each individual Christian as well as the entire body of Christianity, and the power of a bit of leaven to corrupt the whole. From these images and the message they transmit, several momentous consequences flow: the constant need to imagine Jewish plots against Christian purity, the belief that Christians are truly part of one body so that the violation of one is the violation of all, Eucharistic martyrdom even at times without persecution, and tales intended to show that the Eucharistic object, whether host or Christian body, always triumphed over Jewish devilry in the end.

In order to maintain their purity, Christians proscribed physical contact with Jews, passing laws that prohibited eating, residing, serving domestically, and having sexual relations with Jews. Stow argues that Christianity violated its own ideals by this obsession with purity, as its claim that the Church supersedes as true Israel was intertwined with its claim to transcend and render obsolete Jewish legalism. By focusing on ritual purity with regard to the Eucharist, Stow argues, the Church paradoxically undermined its raison d’être.

Readers might have been better served by a less-tangled presentation of the complicated strands Stow weaves together in this book. But there is no question that we are in the hands of an accomplished historian who has enlarged the canvas and opened fresh questions and perspectives on this vexing subject.