Analysis of information sources in references of the Wikipedia article "Subbotniks" in English language version.
There were very few Jews in the Russian empire before 1772 and there is no indication of direct contact between Jews and the early Spiritual Christians... Most dramatically, in the late eighteenth century, the so called Subbotniks or Sabbatarians – ethnic Russians from the central and southern provinces – even turned away from the fundamental Christian doctrines of the Incarnation and the messiahship of Jesus to embrace the Mosaic law of the Old Testament. As the work of Aleksandr Lvov, Aleksandr Aleksandrovich Panchenko, Sergey Shtyrkov, and Nicholas Breyfogle demonstrate, these Russian sabbatarians developed strong communities that survived the severe persecution of both the imperial and Soviet governments. Although the Subbotniks did not, as a rule, follow the Talmud, some of them began follow other practices of different Jewish communities, both talmudic and non-talmudic, even as they retained their separate ethnic identity. In the religious census of 1912, the Department of Spiritual Affairs of the Interior Ministry noted the presence of 8,412 Subbotniks who had fallen away from Orthodoxy, 12,305 Judaizing Talmudists, and 4,092 Russian Karaites.
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