<p>This article traces the emergence of economic antisemitism in medieval Europe. Building on the author’s research showing that most Jews were not professional moneylenders, this article argues that economic antisemitism began with the theological construction of the Jewish usurer as a by-product of an ecclesiastical campaign against usury by Christians. With the rapid rise of crusading and antisemitic blood libels in the later twelfth century, this hermeunetically constructed Jewish usurer was imagined not only as greedy, deceitful, and materialistic, but as intent on injuring Christ, the church, and Christian society. By the thirteenth-century, canon lawyers and theologians narrowed the definition of usury from an immoral desire for ‘more than was given’ to the Roman law contract for loaning money, a mutuum. All Jews then were defined as ‘publically known usurers’ because it was publically known that Rabbinic law, following Deut. 23:20–21, permitted Jews to take usury from “strangers” (i.e. Christians) but not “brothers.” In the thirteenth-century, kings and lords, particularly in England and France, regulated Jewish moneylending at the request of the papacy. By the late thirteenth-century, kings and lords at the encouragement of friars were expelling Jews from their lands as a pious act in part motivated by the theological definition of all Jews as public usurers.</p>