arose in a cultural context very different from that of high and late medieval Europe. The Roman Empire was religiously pluralistic, especially before the mid-fourth century. Several emperors and jurists of the second and third centuries CE nonetheless objected to conversion to Judaism, in particular on the grounds that it drew individuals away from participating in civic and imperial rituals.17 In the meantime, conversion to Judaism coalesced as a Jewish legal process whose key components were the acceptance of the commandments of the Torah, circumcision, and ritual immersion for men; and the acceptance of the commandments and ritual immersion for women.18 The requirement of circumcision for men rendered conversion to Judaism uniquely repugnant to Roman sensibilities. Like many Greeks, many Romans regarded circumcision as a particularly unseemly type of bodily mutilation.19
During the second century CE, Romans began to enact laws against conversion to Judaism. The spirit of this legislation was rooted in an ethos specific to the Roman Empire. This legislation sometimes was adopted in later contexts, however, such that it bore an important legacy. Emperor Antoninus Pius (138–62 CE) decreed that Jews who circumcised non-Jews would suffer the same punishment as castrators—namely, the death penalty and confiscation of property.20 According to the Historia Augusta, Emperor Septimius Severus (193–211 CE) forbade his subjects from “becoming Jews” under threat of heavy penalties.21 At the end of the third century, the jurist Julius Paulus declared in his Sententiae that “Roman citizens who suffer[ed] that they themselves or their slaves be circumcised in accordance with the Jewish rite [we]re [to be] exiled perpetually to an island and their property [was to be] confiscated; the doctors [who performed the circumcisions were to] suffer capital punishment.” This text survived in Emperor Justinian’s Digest (530–33), whose rediscovery at the turn of the twelfth century prompted a revival of the study of Roman law.22
Over the course of the fourth and fifth centuries, as Christians grew in influence within the empire, Roman attitudes toward non-Christians hardened and formal conversion to Judaism assumed new significance. Christian Roman emperors perpetuated earlier prohibitions against joining the Jewish fold. They also advocated for more deliberate boundaries between Christians and Jews, and they threatened severe penalties for Jews who tried to prevent members of their community from converting to Christianity, for non-Jews who sought to join the Jewish community, and for Jews who welcomed proselytes.23 The church fathers (influential Christian theologians of the first centuries of the Common Era) defined Christians and Christianity in opposition to Jews and Judaism, such that Christian apostasy to Judaism involved defecting to a rival community. Moreover, it involved joining the ranks of the archvillains in Christian history, a people whom the Gospels cast as having not only rejected Christ but also caused his death. In addition, Christian apostasy to Judaism represented a reversal of the course of Christian salvation history, the putative progressive unfolding of time on which Christian supersessionism was predicated.24 As the sign par excellence of Jewish-Christian difference, circumcision constituted an especially marked affront to Christianity. St. Paul had deemed circumcision as observed by contemporary Jews to be spiritually void; he extolled a spiritual alternative, “circumcision of the heart.”25
During the first millennium, Christian authorities were especially critical of the Jewish practice of circumcising male slaves upon acquisition, which was rooted in biblical law (Gen. 17:12–13). Upon emancipation, these slaves became full converts to Judaism.26 In an attempt to end this practice, in 335, Emperor Constantine declared that slaves whom Jews circumcised would automatically become freemen. In 339, he threatened Jews who circumcised slaves with the death penalty.27 Merovingian church councils condemned the conversion of slaves to Judaism, as did Visigothic legislation.28 A sixth-century legend about the bishop of Paris St. Germanus (d. 576) depicted Germanus as having heroically intervened to prevent Jews from converting a young slave to Judaism. According to this tale, which was recorded by the poet and bishop Venantius Fortunatus (d. ca. 600), Germanus miraculously broke the bonds of a boy whom Jews were leading about the countryside in chains “for being unwilling to subject himself to the Jewish laws.”29 Over the course of the ensuing millennium, popes and church councils repeatedly forbade Jews to convert their slaves to Judaism.30
The issue of slave conversion aside, Christian expressions of concern about Christian apostasy to Judaism—and about Jews as agents of apostasy—dwindled over time. Exceptionally, in ninth-century southern Gaul, bishops Agobard and Amulo of Lyon decried alleged Christian attraction to Judaism and alleged Jewish efforts to convince Christians that Judaism was superior to Christianity.31 Into the twelfth century, however, Christian anti-Jewish writings sought primarily to expose Judaism’s theological errors and expound on the ways in which Jewish scriptures supported Christian doctrine.32 Through the end of the twelfth century, the notion that Christians who were not slaves might formally convert to Judaism seems to have been far from churchmen’s minds.
The Thirteenth-Century Resurgence of Christian Concern
The turn of the thirteenth century witnessed two interrelated developments. First, Christian authors increasingly depicted Jews as spiritually corrupting Christians.33 They described Jews as distancing the Christian servants who lived in Jewish homes from faith in Christ.34 They also portrayed Jews as publicly mocking Christian doctrine. In 1205, for instance, Pope Innocent III informed King Philip Augustus of France that he had heard that Jews in France were openly proclaiming that Christians believed in a peasant who had been hanged by the Jewish people and that Jews ran around town on Good Friday, laughing at Christians for adoring the Crucified One. Jews did these things, the pope explained, expressly in order to turn Christians away from “the duty of [Christian] worship.”35 Between 1227 and 1230, the first of thirteen articles proposed for discussion at a provincial synod of the archdiocese of Tours likewise contended that Jews were brazenly ridiculing Christianity. It stated that Jews, “the enemies of the Christian faith,” should be expelled from small towns and villages because they were asserting that it was impossible for a virgin to conceive, for a closed womb to give birth, and for the true body of the Lord to look like bread.36 During the third quarter of the thirteenth century, the influential Franciscan preacher Berthold of Regensburg (d. 1272) cautioned his audiences that Jews engaged “simple” Christians in informal religious disputations in order to erode their faith. “You are so unlearned,” he explained, “whereas [the Jews] are well-trained in Scripture. [The Jew] has thought out well for a long time how he will converse with you, in order that you might thereby become ever weaker in your faith.”37 In 1289, King Charles II of Naples—who was also Count of Provence and Forcalquier, Prince of Achaea, and Count of Anjou and Maine—justified his expulsion of the Jews from Anjou and Maine by way of reference to a litany of alleged Jewish misdeeds. The first item on this list was the charge that Jews “deceitfully turned many people of both sexes who [we]re considered adherents of the Christian faith away from the path of truth.”38
Second, early in the thirteenth century, Christian expressions of concern about formal Christian apostasy to Judaism reemerged. One example surfaces in the critique of contemporary monastic life, the Speculum ecclesiae (Mirror of the Church, 1216), of the widely traveled Cambro-Norman archdeacon Gerald of Wales. Gerald reported that two Cistercian monks had “cast away their garments, abandoned their household,” and apostatized to Judaism. The first monk, Gerald wrote, “had himself circumcised in the Jewish rite” and “damnably joined himself to the most despicable enemies of the cross of Christ.” The second monk, whom Gerald specified was from Garendon Abbey in Leicestershire, allegedly “flew off with swift and wicked wings to Judaism, the domicile of damnation.” According to Gerald, when the Oxford archdeacon Walter Map (d. ca. 1210) heard about these two apostates, Map exclaimed that he had never before heard of men of any profession or rank apostatizing to Judaism.39 This remark underscores the novelty in Map’s milieu of the notion of Christian apostasy to Judaism. Gerald was a notoriously imaginative reporter, and the veracity of his account may reasonably be questioned. His primary interest in this passage was to criticize the Cistercian monastic order.40 Thus, he intimated that these two monks were
