The nature of the Christian sacrament of baptism created special problems when it was carried out compulsorily, which differentiated it sharply from forced conversion to Islam (see *Anusim; *Jadid al-Islam). There is evidence that when Christianity established itself as the dominant religion in the Roman Empire, from the fourth century, large numbers of Jews were forcibly baptized: a detailed account is extant of the process in the island of *Minorca in 418. In due course, the church doctrine regarding this matter crystallized. From the time of Pope *Gregoryi, it was generally agreed that by its very nature baptism should be accepted willingly and not imposed by force. Various problems however still remained. It was difficult to define what baptism by force actually implied, apart from sheer physical immersion: did it cover also "willing" acceptance of conversion under menace of death, or under a remoter anticipation of violence, or with the alternative of expulsion? Moreover, when baptism was illegally imposed, did it remain valid, or was the victim at liberty to return to his former faith unmolested? This last was a peculiarly complicated problem in the context of medieval Christianity, for if baptism was valid however conferred, the backsliding was an act of heresy, punishable by death according to the code later elaborated by the Inquisition. In any case, the conception of forcible baptism did not apply in the case of the children or grandchildren of the unwilling converts, who were frequently taken by their parents to church for baptism as a matter of routine when they were born (see *Conversos, *Marranos). Another problem presented itself in the case of infants: at what age could they be presumed to have minds of their own and to accept baptism "willingly" and not passively, or in return for some trivial temptation? On the whole, it may be said that whereas the church doctrine on the matter of forced baptism, which it theoretically condemned, remained unchanged, its attitude as regards ex post facto problems hardened through the centuries.
In the seventh century a wave of forced conversions spread over Europe, sparked off when in 614 Emperor *Heraclius forbade the practice of Judaism in the Byzantine Empire. He is said to have summoned his fellow sovereigns to follow his example; and similar steps were taken in Gaul in 626 by King Dagobert; in Italy in 661 by the Lombard sovereign Perctarit; and in Spain from 616 under successive Visigothic rulers. In the Byzantine possessions, including southern Italy, Heraclius' example was imitated in 873–4 under *Basil i. It is difficult however in most such cases to determine how effectively, and for how long a period, the edicts were put into execution; while on the other hand it is debatable how far baptism with the alternative of exile can be strictly considered in the category of "forced conversion." Moreover the mob sometimes took matters into its own hands and imposed baptism on the steadfast believers who had prepared themselves for the heroic alternative. This is what seems to have happened for example at the time of the campaign of the Byzantine emperor *Romanus i Lecapenus in 932–36 to suppress Judaism in his dominions, when a number of Jewish leaders died rather than submit.
Apart from such cases of mass baptism to escape expulsion as mentioned above, the earliest recorded instance of forced baptism in the more restricted sense seems to have been shortly after 820 in Lyons, where as part of his campaign to convert the Jews (described in his Epistola de baptismo Judaicorum), Archbishop *Agobard of Lyons assembled the children who had not been sent into safety by their parents and baptized all those who to his mind appeared to show some desire for conversion. When about 938 the archbishop of Mainz asked Leo vii whether he should force the Jews of his diocese to be baptized or expel them, the pope advised on the latter course. Many Jews, especially in the Rhineland, were baptized literally by force during the first and subsequent *Crusades, and the antipope *Clementiii protested violently against their being permitted subsequently to revert to Judaism. On the other hand, after Benedict, the leader of the Jews of York was forcibly baptized on the day of Richard i's coronation (Sept. 3, 1189), the archbishop of Canterbury declared that if he desired to return to worship the devil he should be given free choice. One of the clauses in the Constitutio pro Judaeis issued by successive popes (including some of those least favorable to Jews) from the beginning of the 12th down to the close of the 15th century (see *Popes) declared categorically that no Christian should use violence to force Jews to be baptized so long as they were unwilling – though without specifying what was to happen if the illegal process actually took place. Indeed, Pope *Innocentiii, in a letter of 1201 to the archbishop of Arles, considered that a Jew who submitted to baptism under threat of force expressed a conditional willingness to accept the sacrament, with the corollary that he was not at liberty to renounce it. On the other hand, Innocent iv in 1246 categorically forbade the forced baptism of children, the same presumably applying a fortiori to adults. However, in the last decades of the 13th century the strength of the Jewish communities of the Kingdom of Naples was broken by a wave of forced baptisms, sparked off by an apostate from Trani named Manuforte: the descendants of the victims, known as neofiti (see *Crypto-Jews), long remained a recognizable group, suspected of secret fidelity to their ancestral religion.
The events in the Kingdom of Naples in a way set the example for the wholesale wave of compulsory baptisms which swept Spain in and after 1391. This left in its train the phenomenon of the Marranos, which continued to be a problem in the Iberian Peninsula for centuries to come. It may be noted that a very large number, perhaps the majority, of these insincere conversions, especially after the initial episodes, were not the immediate result of actual violence, but were ostensibly quasi-spontaneous in anticipation of it or as the result of moral rather than physical pressure. This did not however apply to the large-scale happenings in Portugal in 1496/97, when practically the whole of the considerable Jewish community of that country were hounded into Christianity by actual violence or were baptized forcibly notwithstanding their protests. This explains the greater tenacity of Marranism in that country in subsequent generations, and down to the present day.
Pope *Martinv categorically forbade (c. 1419) the baptism of Jewish infants below the age of 12 without the parents' permission, to counteract an abuse which was at this time becoming widespread. But a new chapter in the history of forcible baptism began with the institution in Rome in 1543 of the House of *Catechumens (Casa dei Catecumeni), speedily followed in other cities. To justify their existence these institutions had to elaborate a system of propagating the faith, in which ultimately it became difficult to differentiate force from persuasion. Any person who could be imagined by whatever casuistry as having shown an inclination toward Christianity, or who could be considered to be under the authority of a person already converted, could be immured in the House of Catechumens in order to "explore his intention," meanwhile being submitted to unremitting pressure. In 1635 it was decided that the baptism of the head of a household could entail, if he expressed the desire, that of all those members of his family who were under age or dependent upon him, and this was subsequently extended to cover even more remote cases. There had moreover grown up a popular superstition that any person who secured the baptism of an unbeliever was assured of paradise, this leading to a spate of such ceremonies, verging on parody in execution though not in their tragic outcome, throughout the Catholic world.
At Reggio Emilia, during the plague of 1630, a barber summarily christened after his own style 17 or 18 Jewish children in the pest-house that had been set up – the survivors being thereafter brought up as Christians. In 1747 Pope *Benedictxiv decided that once baptized, even against the prescriptions of canon law, a child was to be considered a Christian and educated under church influence. In 1762, the son of the rabbi of Carpentras was pounced on and baptized in ditch water by a callous ruffian and thereafter lost to his family. The kidnapping for baptism of Terracina children in 1783, at the request of a remote relative, caused a veritable revolt in the Roman ghetto. Similar abuses took place in the Catholic lands of Central Europe and in Poland, where the *Jesuits were said to be the principal culprits in the mid-18th century. After the Napoleonic wars, the abuse in its worst form was restricted to those areas in Italy where the popes, now driven by circumstances into reaction, still wielded temporal power. The best-known instance was the *Mortara Case (1858) in Bologna; but it was neither the worst nor the last. In the Russian Empire in the second quarter of the 19th century the institution of the *Cantonists – involving the virtual kidnapping for military service of Jewish male children from the age of 12, or even 8 –was introduced in the expressed hope of compelling them to abandon Judaism. The number of forced or virtually forced baptisms which resulted probably exceeded all similar cases in other lands throughout history. During the Nazi persecutions in Central and Eastern Europe in 1940–45, many Jewish children were baptized by well-meaning Christians in order to help in saving their lives, or when contact with their parents was lost.
B. Blumenkranz, Juifs et Chrétiens dans le monde occidental (1960), index s.v.baptême; S. Grayzel, The Church and the Jews in the xiiith Century (19662), index s.v.Baptism, involuntary and Conversion, of Jews; J. Parkes, Conflict of the Church and the Synagogue (1934), index; Roth, Italy, index; idem, Personalities and Events in Jewish History (1953), 256–74; idem, Gleanings (1967), 240–63.