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Jewish conversions to Christianity in Eastern Europe were infrequent in both premodern and modern times. Mass conversions to Christianity occurred at two intervals: to Eastern Orthodoxy during the Khmel’nyts’kyi uprising (1648–1649; gzeyres takh vetat), and to Catholicism by followers of Jakub Frank in the second half of the eighteenth century. Jewish and Christian sources suggest that individual conversions to Judaism also took place.

Jewish Converts to Christianity in Pre-Partition Poland (before 1772)

Until the late seventeenth century, when the Catholic Church in Poland began making overtures to Jews and other non-Catholics, there had been no organized effort in that country to convert Jews to Christianity. It was at this point that various religious orders, most prominently Jesuits and Franciscans, commenced broader missionary activities with the aim of bringing non-Catholics to Catholicism and teaching existing Catholics to practice the tenets of their faith. These efforts peaked in the eighteenth century. In the 1740s and 1750s, Bishop Franciszek Kobielski of the Łuck diocese preached to Jews and Protestants in synagogues and churches “so that they may convert.” His efforts followed those of Jan Turczynowicz of Wilno (Vilna), a priest who in 1737 had founded the female religious order Sisters of Mariae Vitae, with the goal of converting Jewish girls and women. The order was officially disbanded in 1774, although a few members persisted in their activities into the nineteenth century.

The Catholic church began to address the question of Jewish converts in its legislation only in the eighteenth century. In 1733, the Synod of Płock published a bull, originally issued in 1704 by Pope Clement XI, on Jewish converts to Catholicism. Its message was also translated loosely into Polish in pastoral letters dated 1737 by Bishops Josaphat Michał Karp of Samogitia (Żmudź) and Jan Aleksander Lipski of Kraków. The bull dealt with the education of potential converts, encouraged forced preaching to Jews, and emphasized the importance of providing financial assistance to Jews who converted. It asserted that new converts were to be fully accepted into the Catholic community.

Polish state legislation dealt with neophytes only rarely. In 1588, the Third Lithuanian Statute allowed for the ennoblement of Jews who converted to Catholicism. This law was applied in the Grand Duchy of Lithuania and, on some occasions, in the Crown territories of the Polish–Lithuanian Commonwealth. In 1764, the Polish Sejm revoked the ruling, perhaps as a result of mass conversions instigated by Jakub Frank and his followers in the late 1750s and early 1760s. The law of 1764 stated that converts who had enjoyed the privileges of nobility were to be reduced in status to either the burgher or the peasant estate; if they owned lands, they had to sell them within two years or the properties would be confiscated. An amendment in 1768 excluded from its sanctions converts from the Grand Duchy of Lithuania who had changed their religion prior to 1764. A loophole allowed for the ennoblement of individual converts.

While some converts chose Christianity out of genuine belief in its doctrines, most appear to have accepted the new religion for practical reasons, including for social advancement and the possibility of entering the nobility (though most never achieved this distinction). Jan Abraham Ezofowicz, for example, converted to Catholicism in 1488 and became a prominent royal official and eventually was ennobled. Many converted for economic reasons, as was the case with the Helicz brothers, the first printers of Jewish books in Kraków, who converted to Catholicism in 1537 after having fallen into debt. Two of the brothers were subsequently granted the rights of citizenship in Kraków. Jewish criminals sometimes accepted Christianity in exchange for reduced prison sentences. Jewish women occasionally converted because they had been abandoned by their husbands without a divorce and were, according to Jewish law, unable to remarry. Baptismal records indicate that female converts frequently married Christians almost immediately after converting. Children sometimes converted with their parents, or were baptized by their wet nurses without the knowledge and approval of their Jewish parents.

Both Jewish and Christian sources show that in the wake of the Khmel’nyts’kyi uprising, many Jews who had converted sought to return to Judaism. In 1650, King Jan Kazimierz issued a universal that allowed Jews who had been forcefully converted to Eastern Orthodoxy to return to Judaism. Rabbinic sources from that period attest, however, to many conversions to Christianity that took place during the uprising, addressing halakhic questions on such issues as marital status, inheritance, or rules for divorcing spouses who had been converted. Polish rabbis also addressed the question of accepting repentant apostates back into Judaism (while such individuals had traditionally been accepted, in early modern Poland those who left Catholicism were harshly punished according to Polish law, causing rabbis to have reservations about welcoming them).

Records of the Christian courts and religious orders provide further information about Jewish converts to Christianity. After baptism, converts often assumed new names. Some appellations were derived from names of towns (Bracławski, Stanisławski, Ostrowski); others from the names of months during which the conversion took place (Lutyński [Pol., luty, February], Styczyński [styczeń, January] or Majowski [maj, May]). Some designations stressed the person’s will to convert (Dobrowolski from dobra [good] and wola [will], Dobrochocki from dobra ochota [good willingness], or Zwoliński stemming from z [from] and wola [will, willingness], i.e., from will, willingly).

Although the majority of Jewish converts of the premodern period chose to become Catholic, or, in the eastern territories of the Polish–Lithuanian Commonwealth, Eastern Orthodox, Protestant missions were briefly active in the second quarter of the eighteenth century in western areas. The Halle Institutum Judaicum et Mohammedicum provided Poland with missionaries equipped with linguistic skills and books in Yiddish to convert Jews to Lutheranism.

Jewish Conversions to Christianity after 1772

In nineteenth-century Poland and Russia, as elsewhere in Europe, Jewish conversions were linked to political and economic upheavals within the Jewish community. In times of hope and optimism (during the Napoleonic wars, for example, or in the 1860s when ideas of emancipation and reform were being discussed), the numbers of conversions were relatively low. In times of crisis, however, these levels tended to rise. A pattern was especially evident among the most affluent Jews, who had higher hopes for emancipation, and who had the most to lose when such hopes failed. In Russia, conversion numbers tended to rise during restrictive regimes, dropping during the reigns of more liberal-minded tsars.

Poland (Duchy of Warsaw; Kingdom of Poland).

Over the course of the nineteenth century, the majority of Warsaw’s most affluent Jews converted to Christianity; these numbers peaked during the 1880s and 1890s. In the years immediately following the final partition of Poland (1795), most converts chose to adopt the state religion, Catholicism. After the partitions, however, the Polish territories were controlled by non-Catholic powers, and Jews who converted to Christianity still stood to gain but no longer particularly benefited from a switch to Catholicism. Subsequently, Protestantism became the religion of choice. Between 1821 and 1907, the Protestant London Society for Promoting Christianity among the Jews converted 949 Jews, effecting this action even when the organization was banned by the government for the 20-year period between 1854 and 1874.

The majority of converts in the first half of the nineteenth century came from the lower economic strata of Jewish society, though by the end of the century conversions from these groups decreased to proportions representing less than 15 percent of the converted population. Upper- and middle-class converts then dominated. Data from Warsaw suggest that most nineteenth-century converts (more than 60%) were male, implying professional gain as the motive for such decisions. Nearly 90% of the converts chose Christianity while they were in the first three decades of their lives.

By the latter half of the nineteenth century, Jewish converts to Christianity were distrusted in Polish society. Polish literature provides numerous examples of such sentiments. The works of Ignacy Kraszewski’, Para czerwona and Żyd, both feature converts as unsavory characters. A Jewish character in Bolesław Prus’s well-known book, Lalka, sums up the unpleasant position of Jewish converts to Christianity: “[A]s a Jew I am despised by Christians, but as a convert I’d be despised by Christians and Jews alike.” With rise of antisemitism, a number of writers and public figures (including Teodor Jeske-Choiński and Ludwik Korwin) made efforts to expose the Jewish origins of certain Polish Christians.


Nineteenth-century Jewish converts in Russia included two broad categories of former Jews: involuntary and voluntary converts. Among the first group were cantonist soldiers who had converted under Nicholas I and children who had been baptized by their parents. Perhaps the most famous case of a child who had been converted involuntarily was Vladimir Medem, later a leader of the Bund. Voluntary converts included members of the upper-class bourgeoisie and Jews seeking educational or professional advancement. Daniil Khvol’son, a professor of Semitics in Saint Petersburg, was a prominent example. Explaining his motivation for conversion, he said, “I believe that it is better to be a professor in Saint Petersburg than a melamed in Eyshyshok.” There were undoubtedly also cases of conversion out of religious conviction. Among the converts were Jewish criminals, who until 1862 could have their sentences reduced or overturned if they accepted Christianity. In Russia, single Jewish women appear to have outnumbered single Jewish men among the converts. As in Poland, women’s conversions were typically followed by immediate marriage to a Christian.

Of the 85,000 recorded conversions of Jews to Christianity in nineteenth-century Russia, more than 65,000 converted to Russian Orthodoxy. Initial attempts to convert Jews, however, were not successful; although Tsar Alexander I (r. 1801–1825) established a Society of Israelitish Christians and agreed to grant wide privileges and land to Jewish converts, his measures failed to attract Jews. Tsar Nicholas I (r. 1825–1855) was more successful: in 1854 alone, almost 4,500 Jews became Christians. His policy of drafting young Jews into the tsarist army resulted in a growth in the number of conversions; indeed, about 30 percent of Jewish converts in Russia came from the population of conscripts. Under the more liberal reign of Alexander II (r. 1855–1881) the number of converts dropped, only to rise again after the violence of 1881–1882 and the new restrictions and quotas that affected Jews seeking higher education or professional employment as lawyers or doctors. In 1905 a law was passed that allowed Jewish converts to Christianity to return to Judaism. While the legislation ushered in a wave of requests to do so, subsequent pogroms resulted in a decrease of the rate of return and an increase of the rate of conversion. Unlike in other countries, Jewish converts to Christianity in Russia were not allowed to change their family names, and so they continued to manifest their Jewish origins.


The Austro-Hungarian government of Maria Theresa (1740–1780) and Joseph II (1765–1790) encouraged Jews to convert to Catholicism. Decrees in 1780 and 1783 granted converts privileges, including city citizenship at no financial cost. Until 1775, the age of consent was set at seven, and according to Imperial Law, children of baptized fathers were automatically baptized, even without their mothers’ consent. Many affluent Jews chose to convert to Christianity in order to raise their civic status. For wealthy Jews in the nineteenth century, ennoblement was a reward for conversion, and in Hungary, conversions could be construed as expressions of Magyar nationalism. In 1867, the Interconfessional Law was passed, requiring converts to complete forms stating their previous affiliation and providing details about age, marital status, and occupation. The status known as confessionless, popular in Western Europe, was not an option in Austro-Hungary until late in the nineteenth century. About 20,000 conversions took place in Hungary between 1867 and 1918.

Records from Prague have been partially preserved for 1868–1917. Census material from the Bohemian and Hungarian territories indicates that in Bohemia the annual rate of Jewish conversions to Christianity in the 1890s and 1900s stood at about 0.1 percent of the Jewish population; in Hungary the level was 0.05 percent. These rates began to rise after 1895 when, as elsewhere, anti-Jewish restrictions on higher education (the numerus clausus) encouraged conversion.

It has been estimated that in Prague or Brno at the beginning of the twentieth century, the conversion rate stood at 2.25–2.5 percent of the local Jewish population. About 340 Jews converted in Prague between 1897 and 1908, while in Brno there were 200 in 1900. Data from Prague from 1868 through 1917 suggest that of those who left the Jewish community, about 75 percent converted to Christianity, including half of these to Catholicism. The remaining quarter declared themselves confessionless. The same sources suggest that approximately 5 percent of those who left Judaism, including children from mixed marriages, rejoined the Jewish community later in their lives.

Before World War I, most converts were female and single. Immediately after the war, though, males outnumbered females among the converts by 10 percent. Conversions peaked in 1919–1920 and again in 1934–1938. A Nazi-era census classified approximately 10 percent, or some 80,000 members of the Hungarian Jewish population, as “Christian Jews.”

Christian Conversions to Judaism

Medieval and early modern Christian sources from Eastern Europe reveal that Christians feared a Jewish religious influence on the local population. Some scholars have argued that evidence of Jewish slave-ownership in medieval Poland implied Jewish proselytizing, since accordance to ancient halakhah, male slaves needed to be circumcised if they were to remain in Jewish households.

In 1537 the Cathedral Chapter in Płock noted that two Christians, Ambroży of Mława and Maciej of Sierpce, celebrated Sabbath and Jewish holidays. Letters from King Sigismund I, Queen Bona Sforza, and other royal officials in 1539–1540 indicate that Jews in Kraków and “other royal towns” were accused of circumcising Christians and sending them to Lithuania and Turkey to join Jewish communities there. The king ordered punishment of those who converted or knowingly harbored converts to Judaism, and his investigations led to abuses against Jews in Lithuania. The controversy coincided with the trial and execution of Katarzyna Malcherowa Weigel, the wife of Kraków councilman Melchior Weigel, convicted to death for apostasy to Judaism in 1539.

Decades later, Shelomoh Luria adamantly condemned the acceptance of converts into Judaism. In his Yam shel Shelomoh (Yevamot 4.49), he stated, “should one of Israel accept [a proselyte], he is a rebel, and is responsible for his own death . . . let his blood be on his own head, whether he himself engages in proselytization, or whether he merely knows of such.” The sixteenth-century phenomenon of Judaizing has been discounted by some scholars as early Protestantism. But evidence from Christian courts suggests that Judaizers were treated differently from Protestant “heretics.”

Despite the apparent drastic consequences for committing acts of proselytism in 1539–1540 and Luria’s subsequent condemnation of the practice, Christians continued to be converted to Judaism throughout the premodern period. In 1644, the Va‘ad Medinat Lita (the Council of Lithuania) forbade the acceptance of converts and addressed the issue of financial liability of the Jewish community as a result of proselytism. This ordinance was repeated in 1647. Nonetheless, Polish court records suggest that Christian conversions to Judaism continued. For example, in 1716 two Christian women were convicted of apostasy to Judaism in the town of Dubno, and the execution in Vilna of a Croat Catholic, Rafał Sentimani, in 1753 contributed to the emergence of the legend of the Vilna Ger Tsedek.

Jewish reluctance to accept Christian converts to Judaism was grounded in Christian laws that prohibited apostasy; such laws punished apostates and those who converted them with death. Rabbi Mosheh Isserles noted in one of his glosses in the Shulḥan ‘arukh that “in these lands [Poland] . . . it is forbidden to convert non-Jews” (Yoreh de‘ah 267:4). The Magdeburg law, which served as the legal framework of Polish cities, and, after 1658, legislation enacted by the Sejm both demanded death penalties for apostasy from Catholicism. In 1768, the Sejm legislation was amended, replacing the death penalty with exile.

For the modern period, few studies of conversions to Judaism exist. Data from Prague suggest that while some Jews who had converted to Christianity returned to Judaism, Christian conversions to Judaism took place as well. The majority of these were single women who likely converted in order to marry Jewish men.

Suggested Reading

Todd Endelman, “Jewish Converts in Nineteenth-Century Warsaw: A Quantitative Analysis,” Jewish Social Studies 4.1 (1997): 28–59; Edward Fram, “Perception and Reception of Repentant Apostates in Medieval Ashkenaz and Premodern Poland,” AJS Review 21.2 (1996): 299–339; Jacob Goldberg, Ha-Mumarim be-mamlekhet Polin-Lita (Jerusalem, 1985); William McCagg, “Jewish Conversion in Hungary in Modern Times,” in Jewish Apostasy in the Modern World, ed. Todd Endelman, pp. 83–107 (New York, 1987); Michael Anthony Riff, “Assimilation and Conversion in Bohemia: Secession from the Jewish Community in Prague, 1868–1917,” Leo Baeck Institute Yearbook 26 (1981): 73–88; Michael Stanislawski, “Jewish Apostasy in Russia: A Tentative Typology,” in Jewish Apostasy in the Modern World, ed. Todd Endelman, pp. 189–205 (New York, 1987); Magdalena Teter, “Jewish Conversions to Catholicism in the Polish-Lithuanian Commonwealth of the Seventeenth and Eighteenth Centuries,” Jewish History 17.3 (2003): 257–283.