A largely abandoned historical hypothesis postulated that Ashkenazi Jews were primarily, or to a large extent, descended from converts to Judaism among the Khazars, a multi-ethnic conglomerate of mostly Turkic peoples who formed a semi-nomadic khanate in and around the northern and central Caucasus and the Pontic–Caspian steppe in the late 6th century CE. It is still sometimes used in antisemitic conspiracy theories and in various anti-Zionist approaches.
The hypothesis draws on medieval sources such as the Khazar Correspondence, according to which at some point in the 8th–9th centuries, a small number of Khazars were said by Judah Halevi and Abraham ibn Daud to have converted to Rabbinic Judaism. The hypothesis also postulates that after collapse of the Khazar empire, the Khazars fled to Eastern Europe and made up a large part of the Jews there. The scope of the conversion within the Khazar Khanate remains uncertain, but the evidence used to tie the subsequent Ashkenazi communities to the Khazars is meager and subject to conflicting interpretations.
Speculation that Europe's Jewish population originated among the Khazars has persisted for two centuries, from at least as early as 1808. In the late 19th century, Ernest Renan and other scholars speculated that the Ashkenazi Jews of Europe originated among refugees who had migrated from the collapsed Khazarian Khanate westward into Europe. Though intermittently evoked by several scholars since that time, the Khazar-Ashkenazi hypothesis came to the attention of a much wider public with the publication of Arthur Koestler's The Thirteenth Tribe in 1976. It has been revived recently by geneticist Eran Elhaik, who in 2013 conducted a study aiming to vindicate it.
Genetic studies on Jews have found no substantive evidence of a Khazar origin among Ashkenazi Jews. Geneticists such as Doron Behar and others (2013) have concluded that such a link is unlikely, noting that it is difficult to test the Khazar hypothesis using genetics because there is lack of clear modern descendants of the Khazars that could provide a clear test of the contribution to Ashkenazi Jewish ancestry, but found no genetic markers in Ashkenazi Jews that would link them to peoples of the Caucasus/Khazar area. Gil Atzmon et al. found evidence that the Ashkenazi have mixed Near Eastern and Southern European/Mediterranean origins, though some admixture with Khazar and Slavic populations after 100 CE was not excluded.: "During Greco-Roman times, recorded mass conversions led to 6 million people practicing Judaism in Roman times or up to 10% of the population of the Roman Empire. Thus, the genetic proximity of these European/Syrian Jewish populations, including Ashkenazi Jews, to each other and to French, Northern Italian, and Sardinian populations favors the idea of non-Semitic Mediterranean ancestry in the formation of the European/Syrian Jewish groups and is incompatible with theories that Ashkenazi Jews are for the most part the direct lineal descendants of converted Khazars or Slavs. The genetic proximity of Ashkenazi Jews to southern European populations has been observed in several other recent studies. Admixture with local populations, including Khazars and Slavs, may have occurred subsequently during the 1000 year (2nd millennium) history of the European Jews." Xue et al. note a wholly Khazar/Turkish/Middle Eastern origin is out of the question, given the complexity of Ashkenazi admixtures.: "AJ genetics defies simple demographic theories. Hypotheses such as a wholly Khazar, Turkish, or Middle-Eastern origin have been disqualified but even a model of a single Middle-Eastern and European admixture event cannot account for all of our observations. The actual admixture history might have been highly complex, including multiple geographic sources and admixture events. Moreover, due to the genetic similarity and complex history of the European populations involved (particularly in Southern Europe, the multiple paths of AJ migration across Europe , and the strong genetic drift experienced by AJ in the late Middle Ages, there seems to be a limit on the resolution to which the AJ admixture history can be reconstructed."
Some anti-Zionists have cited the Khazar hypothesis in an attempt to discredit the claim by modern Jews to the Land of Israel. The Khazar hypothesis is also sometimes cited in antisemitic arguments promoted by adherents of various movements and ideologies to express the belief that modern Jews are not true descendants of the Israelites.
History
1806–1918 Lawrence J. Epstein attributes to the Ukrainian Rabbi Isaac Baer Levinsohn (1788–1860) the first reference of a connection between the Ashkenazi Jews and the Khazars. According to Jacob S. Raisin, Levinsohn expressed the opinion that Russian Jews hailed from the banks of the Volga.: "Levinsohn was the first to express the opinion that the Russian Jews hailed, not from Germany, as is commonly supposed, but from the banks of the Volga [...] Originally the vernacular of the Jews of Volhynia, Podolia and Kiev was Russian and Polish, or, rather, the two being closely allied, Palaeo-Slavonic." Levinsohn wrote in 1828:
The hypothesis was advanced nonetheless earlier, in 1808, by Johann Ewers in his ("On the origins of the Russian state") in the context of an early controversy over the foundations of the Russian state, which pitted scholars espousing a Norman origin for the Varangians against those who argued that these founders of the Kievan Rus' were Slavic and indigenous. Ewers proposed the idea that the Viking/Varangian founders were in fact Khazars. The Russian historian Nikolay Karamzin advanced the claim, asserting that considerable numbers of Khazars had left Khazaria for Kievan Rus' in the time of Vladimir I (980–1015). The German Orientalist Karl Neumann suggested as early as 1847 that the migration of Khazars might have contributed to the formation of the core population of the Jews of Eastern Europe, without however specifying whether he was referring to Judaizing Turks or ethnic Jewish residents of Khazaria.: "The Khazars now disappear from history as a commanding horde, but as is well known, their name has been preserved for hundreds of years and in part to the present day in the lands and seas where they once ruled. Of course, the masses of people from the Yaik [= Ural] to the Danube have always remained the same; the Khazars only lost their lordship to other Turks, to the Pechenegs, the Oghuz and Cumans. Remnants of these peoples, namely the division that adheres to the Mosaic faith, are the Karaites in southern Russia and the former Polish lands, who speak Turkic and also resemble the Turks in their body shape and facial features. The Jews, who as we know were so numerous in the realm of the Khazars, may have migrated from the Crimea to Russia and Poland." ()
Subsequently, Abraham Eliyahu Harkavi suggested in 1869 that there might be a link between the Khazars and European Jews.: Three years later, however, in 1872, a Crimean Karaite, Abraham Firkovich, alternatively proclaimed that the members of his Turkic-speaking sect were descended from Turkic converts to Judaism. This hypothesis, that the descendants of Khazar converts to Judaism formed a major proportion of Ashkenazim, was first proposed to a Western public by Ernest Renan in 1883. In a lecture delivered in Paris before the Saint-Simon Foundation on 27 January 1883, Renan argued that conversion played a significant role in the formation of the Jewish people, stating that:
According to Mari Réthelyi, a Jewish studies teacher writing in the journal Hungarian Cultural Studies, many Hungarian Jews in the late nineteenth century, responding to Magyarization and to Hungarian antisemitism, took up the theory, proposed by Rabbi Samuel Kohn in 1884, that Hungarian Jews, like Hungarian Christians, shared a common ethnic descent from the intermarriage of Khazars and Magyars.
Renan's thesis found an echo soon after, in 1885, when Isidore Loeb, a rabbi, historian and secretary of the Alliance Israélite Universelle, arguing for the cause of Jewish emancipation, challenged the notion that nations were based on races, and the Jews therefore, could be excluded as alien. To the contrary, he argued, they were no different from other peoples and nations, all of which arose from miscegenation: the Jews were no exception, and one could assume, he added, that many German and Russian Jews descended from the Khazars. Similarly, in 1893, Anatole Leroy-Beaulieu, a critic of antisemitism who drew on Renan, queried whether or not thousands of Polish and Russian Jews might have their origins traced back to the "old nomads of the steppes".
Other scholars, such as Joseph Jacobs (1886), expressed scepticism.
The Russian-Jewish physician and physical anthropologist Samuel Weissenberg (1867–1928), using physical measurements of 1,350 Jews in his home town of Elizavetgrad, challenged the idea that east European Jews originated, like German Jews, as migrants from medieval France. Jewish settlement in eastern Europe took place very early, and these rooted eastern communities readily accepted into their midst Khazars who had converted, absorbing many thousands into the Kievan empire. The theory implied Jewish culture predated the rise of Russia, an implication which led Stalin decades later to ban Khazar studies in the Soviet Union. Johann Friedrich Blumenbach (1752–1840), a pioneer of race science and physical anthropology, had argued earlier that the origins of the "European" race lay in the Caucasus. In this context, Weissenberg's formulation, in identifying Eastern Jews as descendants of an intermixture of Jews with the Caucasian Khazars, presented the eastern Jews, long thought inferior or less noble than Western Sephardic Jews, as the authentic, veritable heirs of a European Jewish tradition. In 1903, (1864–1897), in his posthumous treatise entitled The beginnings of Jewish religion in Poland, examined traces of Khazar elements in early Polish history.
In 1909 Hugo von Kutschera developed the notion into a book-length study, arguing that Khazars formed the foundational core of the modern Ashkenazi. Maurice Fishberg introduced the notion to an American audience in 1911 in his book The Jews: A Study of Race and Environment.. Maurice Fishberg, The Jews: A Study of Race and Environment.
When at the Versailles Peace Conference, a Jewish Zionist called Palestine the land of the Jewish people's ancestors, Joseph Reinach, a French Jewish member of parliament who was opposed to Zionism, dismissed the idea, arguing that Jews descended from Israelites were a tiny minority. In his view, conversion had played a major role in the expansion of the Jewish people, and, in addition, he claimed, the majority of "Russian, Polish and Galician Jews descend from the Khazars, a Tatar people from the south of Russia who converted to Judaism en masse at the time of Charlemagne."Quigley, John (1990). Palestine and Israel: A Challenge to Justice. Duke University Press. p.71.
Interwar years, 1918–1939