Crucially, as Chapter 3 shows, during the latter half of the thirteenth century as well as during the fourteenth century, inquisitors in German lands, France, northeastern Spain, and the Italian peninsula prosecuted born Christians who apostatized to Judaism as well as the Jews suspected of having aided them. A variety of inquisitorial writings provide insight into inquisitors’ engagement in the campaign against Jewish “unbelief.” The compilation of short treatises against “the enemies of the church” attributed to the Passau Anonymous gave full expression to the view that alleged Jewish efforts to draw Christians to Judaism formed part of a broader effort on the part of unbelievers to mislead the Christian faithful. One recension announced: “The Catholic faith is assaulted by Jews, heretics, [and] pagans [i.e., Muslims.] [These groups] arouse and seduce to their sects all whom they are able—men and women, laymen, clerics, and regular clergy.” In addition to reflecting and refracting the sense that Jews were one of several groups that indiscriminately assailed faithful Christians, the Passau Anonymous claimed that Jews, Muslims, and heretics employed the same methods—rhetorical persuasion, bribery, and blasphemy—to do so. All three groups allegedly “gloried in their [respective] law[s] and extolled [them] with authorities and explanations, and they enticed their believers [also] by means of temporal promises and by blaspheming [against] the Catholic faith.”120
Thirteenth- and fourteenth-century inquisitorial manuals prescribed the same consequences for “Judaizing” and sliding into heresy. For instance, an anonymous thirteenth-century Bohemian handbook advised that “the house or synagogue in which someone was re-Judaized or hereticized” should be destroyed.121 In addition, inquisitorial manuals devoted chapters to Jews alongside chapters on Christian heretics. The inquisitor of Toulouse, Bernard Gui (1262–1331), who was among the judges who condemned the leper Guillaume Agasse in 1322, opened the chapter on Jews in his widely disseminated Practica inquisitionis heretice pravitatis (Practice of the Inquisition of Heretical Depravity, ca. 1324) by thundering: “The faithless Jews try whenever and wherever they can secretly to mislead Christians and drag them into Jewish unbelief.”122 As Chapter 5 considers, Gui’s manual and at least four other thirteenth- and fourteenth-century inquisitorial guides directed inquisitors to interrogate Jews specifically about the manner in which they circumcised Christians.123
During the last decades of the thirteenth century, at the same time as inquisitors increasingly prosecuted apostates to Judaism and their purported Jewish abettors, lay and ecclesiastical leaders persisted in promoting conversion to Christianity. Dominicans established schools where friars were to study Arabic and Hebrew, partly in order to aid in their missionary efforts.124 Around 1270, the Catalan Dominican Raymond Martini penned the massive Pugio fidei adversus mauros et iudaeos (Dagger of Faith Against Muslims and Jews) as a handbook for Christian missionaries. In England, France, and Catalonia, kings commanded Jews to attend conversionary sermons.125 As in earlier years, however, Christian conversionary efforts proved disappointing. Muslims converted to Christianity in lands that came under Christian rule, but few were baptized in Muslim realms. In 1274, Humbert of Romans lamented that the very few Muslims who had ever been baptized were captives and that these converts seldom became good Christians.126 Jewish conversions, too, continued to fall short of Christian ideals.127
Christian sources from the last decades of the thirteenth century and the first decades of the fourteenth reveal a number of ways in which Christian concerns about Christian apostasy to Judaism continued to participate in a broader preoccupation with the changeability of religious affiliation. For instance, Christian authors in various parts of Europe contemplated the possibility that an agent of conversion to a particular faith could become an apostate from that same faith. Recognizing that Jewish-Christian encounters—and religious debates in particular—could lead to crossings of the boundary between Judaism and Christianity in two directions, the anonymous redactor of the Mallorca Disputation (1286) noted that it was agreed at the outset of this debate—likely in jest, but suggestively nonetheless—that the loser would convert to the religion of the winner. If the Jew were to be defeated, he “would be made a Christian and be baptized”; if the Christian were to be defeated, he would “be made a Jew and be circumcised.”128
This was not a new trope. According to the Gesta regum Anglorum (Deeds of the English Kings) of English historian William of Malmesbury (d. ca. 1143), in the late eleventh century, the second Norman king of England, William Rufus, swore that if London Jews won a debate against Christian bishops, “he would go over to their sect.”129 Thirteenth-century authors, however, seem particularly frequently to have pondered the interchangeability of the roles of missionizer and missionized. In his collection of saints’ lives known as the Golden Legend, the Italian chronicler and archbishop Jacobus de Voragine (ca. 1230–98) included an anecdote in which Pope Sylvester I (d. 335) offered to consider converting to Judaism during a disputation in which he and his clerks debated against a group of learned Jews. According to this account, when one of the Jews suggested that the contest turn from words to deeds, Sylvester declared that, if the Jews could revive a dead bull, he would believe that they operated by the power of God and not by the power of the devil. For their part, the Jews agreed that, if Sylvester could raise the bull in the name of Jesus, they would believe in Christ.130 Some contemporaneous Christian authors evoked the interchangeability of religious identities similarly in relation to Islam. According to Ramon Llull’s autobiographical Vita coaetanea (A Contemporary Life), in the 1290s, Llull assured Muslims in Tunis—likely in order to draw them into debate—that, if they could convince him of the truth and superiority of Islam, he would convert to Islam.131
The fourteenth-century Old French version of the (now lost) eleventh-century Latin Historia Normannorum (History of the Normans) portrayed a Christian missionary as actually becoming drawn to Judaism. It recounted how “Jews’ rhetoric”—“the venomous sweetness of their words”—temporarily “destroyed the devotion to the [Christian] faith” of a Christian youth who had set out “to dissuade the Jews from their evil belief and faith.” According to this text, “the Jews counseled this Christian [youth] to leave the Son and believe only in the Father,” and “the devil bound [the youth] to the Jews’ words.”132
The notion that encounters between Christians and infidels could result in conversion either to or from Christianity is evident also in the simultaneous circulation of narratives that were closely related, except that one culminated in Jewish conversion to Christianity and the other culminated in Christian apostasy to Judaism. Two types of references to a host desecration charge that was leveled in Paris in 1290 illustrate this phenomenon.133 Latin and French homiletic and chronicle accounts of this host desecration charge portrayed it as having led to conversions from Judaism to Christianity. According to the anonymous De miraculo hostiae (On the Miracle of the Host, ca. 1299), for example, when the Jewish host desecrator threw the host into a cauldron of boiling water, the water became bloody and the host was transformed into a crucifix that hovered above the cauldron. Upon witnessing this miracle, the Jewish culprit’s wife and children converted to Christianity. In addition, “many other Jews, moved by so patent a miracle, converted to the [Christian] faith, as well, and embraced the sacrament of baptism.”134 By contrast, in the same year (1299), in a plea to the justices of his kingdom to cooperate with inquisitors in punishing a spectrum of purported Jewish offenses, King Philip IV, “the Fair,” of France referred to Jewish host desecration not by way of celebrating how associated miracles could lead Jews to convert to Christianity but, instead, by way of warning that Jewish offenses of this nature could lead Christians to apostatize to Judaism. “[By] daring wickedly to handle the most holy body of Christ [i.e., to desecrate the host] and to blaspheme other sacraments of [the Christian] faith,” Philip cautioned, Jews were “seducing many simple Christians and circumcising those whom they had seduced.”135