A Jewish Empire?
Religion and Mission in the Khanate of the Khazars
In 2005, the plan for a monumental statue of the Grand Prince Svjatoslav I (r. 959-972) of Kiev, which was to be built in the village of Cholki near Belgorod (approx. 700 km south of Moscow), caused some excitement in Russia. The artist, Vjačeslav Michajlovič Klykov (1939-2006), was considered an "expert" for such national monuments, but was himself close to the extreme nationalist right and was one of the signatories of the "Letter of the 500" in 2005, in which the Russian attorney general was called to investigate all Jewish organizations in Russia on suspicion of extremism. And so, according to the circulated draft, Svjatoslav, who, along with other neighboring peoples, had also subjugated the Khazars' empire, should be shown on horseback how he races an enemy warrior whose shield adorns a Star of David. Various organizations from home and abroad protested against such a representation of the triumph of the Russian national hero over the "Jewish" Khazars. The press office of the Belgorod regional administration then issued a statement that the monument had not yet been built and that its design would express respect for representatives of all nationalities and religions. In fact, the warrior's shield on the completed monument did not show the Star of David, but a different form of decoration. The debate made it clear, however, how much the existence of a medieval “Jewish” empire could arouse people's minds in Russia even a thousand years after its fall. 
Monument drafted by the sculptor Klykov (1939-2006) in the Belgorod region of Russia, showing Prince Svjatoslav of Kiev defeating a Khazar warrior (https://en.wikipedia.org)
In fact, the conversion of a people to Judaism in the Middle Ages is a very rare event. Even in the Khazar tradition, people were aware of the unusual nature of this process and dressed it in various legends. The story of a competition between the three major monotheistic religions (Judaism, Christianity, Islam) at the court of the Khazar ruler has been handed down to us in several versions, whereby the representatives of Judaism would have won the dispute about the faith - a motive that we also find in the traditions on the the conversions of other peoples. However, the process of converting the Khazars to the Jewish faith is difficult to reconstruct precisely because of this legendary cloak.
2 The ancient religion of the Khazars
What is certain is that the Khazars, like other steppe peoples, originally adhered to the ancient Turkic-Mongolian religion, which centered around the veneration of the sky god Tengri, symbolized, among other things, by the sun. The most important animal of the equestrian nomads, the horse, was sacrificed to him. According to various sources, the Khazars also worshiped sacred trees; these stood for the world tree, which sits enthroned in the middle of the world and connects the underworld, human world and the sky. Elements of shamanism were equally widespread, and various practices were used to try to connect with the world of spirits and ancestors in ecstasy. One of the earliest descriptions of the Tengri religion in the Khazar Empire from a Christian point of view can be found in the historical work of Movses Kałankatwacʽi, who describes the missionary journey of Bishop Israyēl from Caucasian Albania (in modern-day Azerbaijan) to the “Huns” under Khazar sovereignty in today's Dagestan in 681 AD: “They offered horses as burnt sacrifices and worshiped a gigantic wild beast, which they called the god T‛angri χan (…). With a completely disorganized mind, they stumbled into every kind of misconception; (they) beat drums and whistled over corpses, (they) afflicted themselves bloody cuts with swords and daggers on their cheeks and limbs, and they did naked sword fights - oh hell! - at the graves, man against man and group against group, all unclothed for the battle. (...) They made sacrifices to the fire and the water and to certain gods of the paths, and to the moon and to all the creatures that they saw as remarkable in their eyes." 
For the Byzantine-Khazarian border area in the Crimea, the vita of Constantine-Cyril describes the veneration of a holy oak by the local population for around 860 AD (which the saint of course put an end to). This old belief remained with the Khazars after the conversion of the ruling group to Judaism, especially in the ordinary population.
The Central Asian sky god Tengri in a modern Mongolian representation (https://de.wikipedia.org)
3 Christianity in the Khazar Empire
As the journey of Bishop Israyēl shows, the Khazars became the target of Christian mission attempts early after the formation of their empire in the steppes north of the Black and Caspian Seas (between 630 and 660 AD). In fact, we subsequently receive news about Christian communities in the Khazar Empire. The city of Samandar (today's Dagestan) is said to have been largely Christian in the 10th century, and archaeological finds also confirm the existence of Christian communities in towns on the coast of Dagestan. Contact with Christians took place both in the Caucasus and in the Crimea, where Christian cities came under Khazar rule. The former Muslim Abo from Tbilisi was even baptized as a refugee in the Khazar Empire around 782 AD; in his vita (in Georgian language) it is also reported that at this time the Khazar ruler and his entourage were still "pagans" (and therefore not yet Jews). Of course, the Byzantine Empire had a particular interest in the Christianization of the Khazars, which they regarded as valuable allies against the Arabs in the 7th and 8th centuries. In 732/733 AD, the Byzantine Crown Prince Constantine (V) married the daughter of the Khazar Khan. However, there emerged several conflict zone between Byzantium and the Khazars where the spheres of influence of the two empires collided, namely on the Crimean peninsula. Nevertheless, around 840 AD Emperor Theophilos complied with the Khazars' request for support in the construction of the fortress Sarkel at the river Don. And in 860 AD, the subsequent “Apostles of the Slavs” Cyril-Constantine and Methodius were sent to the Khazar court, where, according to their vita, a competition between the three religions took place - in fact at that time the leaders of the Khazars had already become Jews. This ultimate failure of the conversion attempts may have contributed to the estrangement between Byzantium and the Khazar Empire. In the 10th century we often find the two empires in conflict with each other (see below). However, larger Christian communities continued to exist in many places in the Khazar Empire, including the capital of Itil. As early as 855 AD, the Byzantine emperor sent Lazaros, a monk and painter from the Khazar people, as an envoy to Pope Benedict III. In a letter in 919/920 AD, Patriarch Nikolaos I Mystikos reports that he had sent the newly ordained archbishop for the city of Kherson (on the Crimea) to Chazaria because the Christians there had asked for a bishop in Constantinople in order to ordain priest . In a letter he wrote shortly thereafter, we learn that even a bishop should have been appointed for the Khazar community. Christian church life was also possible among Jewish Khazar rulers.
The Khazar Empire around 850 AD (www.geocities.com/ayatoles)
4 The Khazars and Islam
The Khazars also came into contact with Islam at an early stage. However, these relationships were initially primarily of a warlike nature: in the 7th and 8th centuries, the Khazars advanced several times over the Caucasus into the regions of Georgia and Armenia under Arab sovereignty and further south, while Caliphate troops tried unsuccessfully to also gain a foothold north of the large mountain ridge. These centuries-long wars in the Caucasus may have hampered the emergence of Muslim communities in the Khazar Empire. In 737 AD, however, the Khazars suffered a severe defeat against the Arab general Marwan ibn Muhammad; Muslim troops advanced far beyond the Caucasus and eventually even forced the Khan and his entourage to adopt Islam . Although this conversion remained an episode, the Khans probably shifted their imperial center from Dagestan to the lower Volga river at this time, which the Khazars referred to as Itil ("Great River"). When relations relaxed at the end of the 8th century and trade between Mesopotamia, Persia and the north intensified, numerous Muslim traders brought their faith along with their goods. From the end of the 8th century onwards, Muslim mercenaries from the region of Khoresm in Central Asia played a special role. The Khazar rulers incorporated them into their army in large numbers (supposedly up to 7,000 men), and thus strengthened their position towards the contingents of the powerful of the Khazars and other tribes. These mercenaries were promised that they would never have to fight Muslims. The presence of numerous Muslims also led to the conversion of not a few Khazars to Islam; according to Arab reports, there were over 10,000 Muslims and 30 mosques in the Khazar capital of Itil in the 10th century .
The Volga Delta near Astrakhan, near which the Khazar capital Itil was probably located (https://de.wikipedia.org)
5 The conversion to Judaism and its dating
The conversion of the Khazars to Judaism was mainly reconstructed on the basis of three source texts in Hebrew from the 10th century: The first was the correspondence between the Jew Ḥasday ibn Šaprut and the Khazar prince Joseph from around 950 AD. Ḥasday ibn Šaprut was a doctor and vizier under the Umayyad caliphs' Abd ar-Rahman III. (reg. 911-961) and al-Hakam II. (reg. 961-976) on the Iberian peninsula. Through merchants he learned of the existence of a Jewish empire in the east. When a legation went from the Umayyad court in Cordoba to Constantinople, ibn Šaprut instructed the Jewish diplomat Isaak bar Nathan to travel from there to the Khazar Empire; this attempt failed. Another letter by Ibn Šaprut, however, reached its destination around 953 AD through the mediation of Jews in Central Europe by land; Ḥasday ibn Šaprut describes his motivation to seek contact with the Khazar ruler as follows:
We live in the diaspora and there is no power in our hands. They say to us every day: "All people have their kingdom, but you have no memory of it in all the countries." But when we heard from my lord the king about the power of his empire and his powerful army, we were amazed. We raised our heads, our spirits returned, our hands were strengthened, and my lord's kingdom was our defense response.
Indeed, a short time later, Ḥasday ibn Šaprut received an answer in the form of a letter in Hebrew from the Khazar “King” (as he calls himself) Joseph, describing the Judaization of the Khazars and the situation in the empire . In addition, there is another fragmentary letter found in the storage room (Genizah) of the Cairo Ben Ezra Synagogue, the "Schechter text" named after its discoverer Solomon Schechter (1847–1915). Its author also describes himself as the subject of King Joseph . He was probably a Khazar who met the envoy of Ḥasday ibn Šaprut in Constantinople, to whom this earlier letter (probably dated around 949 AD) is also addressed. These texts are characterized by a legendary representation of the conversion of the Khazars to Judaism, which also contradicts itself in essential points, and are only preserved to us in copies of the 11th century, which show clear traces of revision.
Fragment of a copy of the Hebrew letter from Hasday ibn Shaprut to the Khazar ruler from around 950, discovered in Cairo, today in Cambridge (https://www.lib.cam.ac.uk)
According to Joseph's letter, Judaism is said to have spread to the Khazar Empire for the first time through an army leader named Bulan (Turkic for "deer"), who called Jewish scholars into the country and also held a religious dispute between representatives of Judaism, Christianity and Islam. On the other hand, according to the Schechter text, Jews from Armenia fleeing from “idolaters” brought their religion to the country north of the Caucasus, where they lost all writing and could only preserve some external features of the faith such as circumcision and the Sabbath. Only then did a successful Jewish-born military leader initiate further Judaization; he called Jewish scholars into the country and organized a competition between the three religions. According to the letter of Joseph, Judaism was said to have been consolidated under the ruler Obadiah, who bore the name of an Old Testament prophet, who called rabbis into the country and set up synagogues and Talmud schools that ensured the interpretation of the Bible, Mishna, Talmud and the prayer books. The Schechter text has no report on this. The dating of these events in the texts is also not very reliable; in the letter of Joseph, the conversion of Bulan and the subsequent dispute of faith are set 340 years ago, which would correspond to the year 615 AD, but in which neither the Khazar Empire nor Islam existed. The great Spanish-Jewish scholar Yehuda ha-Levi (approx. 1075–1141 AD), who uses the religious dispute at the Khazar court as a framework for his work “Sefer ha-Kuzari”, dated the Judaization of the Khazars 400 years before his time, which is approximately the year 740 . While some scholars advocated this date, others wanted to follow the Arab historian al-Mas‛ūdi, who wrote: "The king of the Khazars had already become a Jew at the time of the Caliphate of Harun al-Rashid [r. 786-809 AD], and to him Jews had come from all countries of Islam and from the land of the Greeks (= Byzantium).” In 1995 Constantin Zuckerman finally identified the dispute of faith mentioned in the Hebrew letters with the one described in the Vita of Constantin-Cyril and therefore dated the conversion the Khazars to Judaism to around 860 AD. However, since 1999 AD, we have had a more secure terminus ante quem for the official conversion of the Khazar rulers to the Jewish faith; this is provided by Khazar imitations of Arab silver coins (dirhem) discovered on the island of Gotland, which bear the inscription "Moses [instead of Mohammed as with the Arab coins] is the messenger of God" (Mūsā rasūl Allāh). These coins date from around 837/838 AD, and at the same time document the importance that the Khazar Empire had at that time for trade between the Orient and Northern Europe .
Khazar silver coin based on the Arabic model with the legend "Moses is the Messenger of God", approx. 837/838 AD (found in Gotland in 1999, https://de.wikipedia.org)
In the Vita of Constantine-Cyril, too, it ultimately becomes clear that the missionary found himself at a Khazar court that was already dominated by the Jewish faith in 860 AD:
The Khan replied to him: "We all speak in the same way, only on this one point do we keep it differently, because you praise the Trinity, but we praise one God, whereby we interpret the Scriptures correctly. "(...) But the Jews who stood around him said to him: "Now say, how can a woman in her body embrace God whom she cannot even see, let alone give birth to". 
Therefore, we can now assume that at least the leading group of the Khazars converted to Judaism in the first decades of the 9th century. The exact circumstances of this process, however, remain unclear. Indeed, ancient Jewish communities, from which the faith could have been transmitted to the Khazars, existed both in Georgia and Armenia and on the Crimean peninsula. Until the end of the 6th century, considerable Jewish population groups can be found there. However, we only have more recent news from around 860, both in the Vita of Constantin-Cyril and in a letter from the Patriarch Photios to Archbishop Antonios of Bosporos, whom he congratulates on the conversion of Jews on the Crimea. As the Schechter text and other sources report, persecutions moved Jews to find their way from Byzantium to the Khazar sphere of power. In the Byzantine Empire, Emperor Herakleios (r. 610-641 AD) is said to have ordered the compulsory baptism of all Jews around 630 AD, although the source evidence is doubtful. A similar measure is attributed to Emperor Leon III (r. 717-741) for the year 721/722 AD. Even though Judaism may have spread into the Khazar Empire since then, there is no evidence for a conversion of large groups of the Khazars or the elite at this point. In the 8th century, contemporary sources still referred to them as “pagans”. In addition to the Jewish communities mentioned, as for the case of Islam, merchants, especially the so-called Rādhāniyya, whose trade network extended from the Atlantic to the Orient and China, may have played a role in the spread of the faith; according to Arabic sources, their activity extended to the Khazar Empire.
It is striking why in the two Hebrew versions Judaism is victorious in the dispute of faith: in the Schechter text, both the representative of Christianity and of Islam have to confirm the narration of the history of creation of the people of Israel, which the Jewish scholars based on the Tora, since it is also the basis of their traditions. In the letter of King Joseph, the Khazar ruler separately asked the representatives of Christianity and Islam which of the other two religions they considered the better; both answered: Judaism. The Jewish faith thus appears as a "third way" to monotheism, which the Khazars integrated into the community of the bearers of a respected book religion. Their princes became rulers who, like the emperor in Constantinople and the caliph in Baghdad, could legitimize their royalty with the model of ancient Israel with the leading figures of David and Solomon, at the same time avoiding to increase the influence of one of the two powerful neighboring empires (Christian Byzantium and the Islamic Caliphate) in their realm. Peter B. Golden is also of this view and refers to the conversion of the Central Asian Uighurs to Manichaeism, also a persecuted, marginalized religion, in 762 AD, "a very public way of proclaiming their ideological independence from China and to sharpen distinctions with their rivals, the Qarluqs and Qirğiz, among whom Nestorian Christianity had made some headway ”.
The contradicting sources on the conversion of the Khazars to Judaism still cause difficulties for research. Shaul Stampfer, an expert on modern Eastern European Judaism at Hebrew University in Jerusalem, therefore even doubted the entire historicity of this process in a recent article (2013). But that would mean "throwing the child out with the bath"; the contradictory nature of the various reports suggests that the various authors did not simply copy a common legendary source, but relied on various observers who encountered Judaism in the Khazar Empire.
The great Jewish scholar Solomon Schechter (1847-1915) in the Genizah (storage room) of the Cairo Ben Ezra Synagogue, in which he also discovered letters from the Khazar Empire (https://en.wikipedia.org)
6 Jewish religious life in the Khazar Empire
To what extend did the Khazars adopt Jewish traditions and laws? The description in the Hebrew letters of the 10th century to Ḥasday ibn Šaprut, according to which synagogues and schools were established and Jewish scholars were brought into the country, who interpreted the Bible, the Mishna, the Talmud and the prayer books, describes a complete religious infrastructure, as required by rabbinical Judaism at the time. Arab authors, in particular, confirm the picture of the Khazar contacts of Ḥasday ibn Šaprut. Ibn al-Faqīh al-Hamadānī, whose work can be dated around 1010 AD, wrote: “And they (the Khazars) took on the difficult obligations that the law imposed on the Torah, such as circumcision, the ritual ablutions, the ablution after the expulsion of the (male) semen, the ban on working on the Sabbath and during the feast days, the ban on (eating meat from) animals that are (prohibited) according to this religion, and so on.” From the letter of King Joseph we also learn that the Khazars adopted the Jewish calendar. A further immigration of Jews in the 9th and 10th centuries mentioned in Arabic sources, for example from Mesopotamia, where Babylonia had been an important center of Jewish life for centuries, and from the Byzantine Empire may have strengthened the connection to the Jewish tradition.
To what extent, however, Judaism was widespread within the Khazars and other peoples under their sovereignty, the Arab historians make contradictory statements. Ibn al-Faqīh al-Hamadānī writes: “All Khazars are Jews. But they only recently became Jews,” and Ibn Fadlān, who traveled in the area around 922 AD, states: “The Khazars and their kings are all Jews” . However, al-Mas‛ūdī describes the religious situation in the Khazar capital of Itil in more detail: “There are Muslims, Christians, Jews and pagans in this city. As for the Jews, these are the king, his entourage and the Khazars from his tribe.” Al-Istahrī, who wrote about 950 AD, even notes: “The Khazars are Muslims, Christians and Jews, and among them are idolaters. The smallest group are the Jews, most of them are Muslims and Christians, with the exception of the king and his noblemen, (who) are Jews." And Ibn Rusta (10th century) also writes: "Their supreme leader is committed to Jewish belief, just as (...) the warlords and the nobles who are with him do; the rest of the Khazars have a religion similar to that of the Turks." 
Finding from the Khazar fortress of Sarkel at the river Don with Jewish symbols (https://upload.wikimedia.org/wikipedia/commons/9/94/Khazars-sarkel.jpg)
One document that was used to demonstrate the wider spread of Judaism in the Khazar sphere of power is the “Kiev Letter”, discovered in 1962. It is a letter in Hebrew from between 870 and 930 AD by a Jewish community in Kiev. The list of signatures includes two officials responsible for the welfare of the community (Parnas), as well as the surnames Kohen (which indicates the descent from the Aaron priestly family) and Levi (as a reference to the descent from the Levi tribe). The background of these community members is controversial in research: were they Jewish immigrants, descendants of Jewish-Khazar or Jewish-Slavic mixed marriages or even Slavic or Khazar converts, who adorned themselves with these venerable names? The Kiev letter therefore cannot be clearly seen as evidence of a wide spread of Judaism among the Khazar population.
If we follow the above mentioned the Arabic sources, Judaism seems to have been limited to the Khazar elites, i.e. the ruler, his entourage, leading clans of the royal tribe and leading members of other tribes. A conversion of larger groups of the population, for example under duress, to Judaism was not attempted by the Khazar rulers. Rather, they took religious diversity into account and established two judges in Itil for Jews, Christians and Muslims and one for the "pagans", the followers of the old religion, as al-Mas alūdī reports to us.
7 Responses to Conversion to Judaism by Contemporaries
While Arab historians described the Khazars' Judaism, contemporary Byzantine sources keep completely silent about the conversion; the same applies to the texts of the other Christian neighboring peoples of the Georgians and Armenians - in contrast to the Latin West. The French monk Christian of Stavelot is even one of the oldest observers of the conversion of the Khazars; around 864 AD, he wrote that "one tribes of the Huns called Gazari is circumcised and adheres to Judaism". On the Byzantine side, we may have a Byzantine commentary on the religious situation in a letter from Patriarch Nikolaos I to the Archbishop of Cherson active in the Khazar country in 920 AD; we read: “We greatly appreciate your zeal for this deceived people, who have almost been taken from the womb of piety by the evil demon, and we exhort (you) to show all possible strength for the care and commitment for their salvation whose aptitude to Christ our God and salvation will be fully restored.” The implied hardship of the Khazar Christians in the midst of this“ deceived people” may indicate the special situation of this community, which lived in an empire ruled by a Jewish elite.
All in all, the failure of Constantine-Cyril's mission from Constantinople, where mission and foreign policy were always closely linked and where otherwise one could celebrate great successes with the Slavic neighboring peoples and the Bulgarians during this time, had caused disappointment. Constantin Zuckerman states: "This act (…) was perceived by the Byzantines as a slap in the face and, of course, as a theological challenge." Perhaps as a compensation, Emperor Basil I (r. 867-886 AD) in ca. 868 issued a decree according to which the Jews in the Byzantine Empire should present the evidence of their belief in disputations or recognize Christ as the head of the law and the prophets. These measures may not have improved the relationship between Constantinople and Itil and may have led to further emigrations of Jews to the Khazar Empire. The latter phenomenon is found in connection with another anti-Jewish measure by a Byzantine emperor. Romanos I Lakapenos (r. 920-944) is said to have ordered in ca. 932 AD to baptize all Jews; al-Mas‛ūdī writes: “Some Jews joined him (the king of the Khazars), who arrived there from various Muslim cities and from Rūm (= the Byzantine Empire). This happened because the King of Rūm, in our time (943) it is Armanūs (Romanos I Lakapenos) who converted the Jews who were in his empire to the Christian faith, exerting coercion on them. “ From the Schechter text we learn that retaliation measures against the Christians on Khazar Empire soil were therefore also carried out without this being specified in more detail.
Copper coin of the Byzantine Emperor Romanos I Lakapenos (r. 920-944; https://de.wikipedia.org/wiki/Romanos_I.#/media/Datei:Romanus1.jpg)
Overall, relations between the Khazars and Byzantium deteriorated significantly in the 10th century. In his work “De administrando imperio” Emperor Constantine VII Porphyrogennetos around 950 AD even gave instructions to his son Romanos “about the country of the Khazars and how to fight it” with the help of its neighbours. The emperor names the Oguz Turks, the Bulgarians (perhaps the Volga Bulgarians) and the Alans (in the northwestern Caucasus) as peoples that could be mobilized against the Khazars . The latter, formerly under Khazar sovereignty, became a target of a Byzantine mission in the 10th century. The Alans actually went to war against the Khazars, but suffered a defeat in 931/932 against Aaron, Joseph's predecessor, which led to the temporary expulsion of the bishop and Christian priests from the Alans and the restoration of good relations with the Khazars.
The Volga Bulgarians also attempted to free themselves from Khazar sovereignty at this time (around 922 AD), but with the help of the Caliph of Baghdad; they converted to Islam. The destruction of a synagogue on Muslim territory, to which the Khazar ruler responded by demolishing the minaret of a mosque in Itil, also led to a temporary clouding of relations with the Muslims. While various vassal peoples tried to gain independence with the help of the neighboring great powers, the Varangian Rus in the north became another expansive opponent, who was also mobilized against Itil by Byzantine diplomacy. While these attacks under Aaron and Joseph could still be fended off in the first half of the 10th century, the weakened Khazar Empire finally succumbed to the attacks of the Rus under Svjatoslav von Kiev, who conquered and looted Sarkel and Itil in 963–965 AD.
Aerial view of the excavations in the Khazar fortress Sarkel at the river Don in the 1930s
8 The thirteenth tribe? The Khazar Empire in the 20th and 21st centuries
Of course, the Khazars did not disappear without a trace after the fall of their empire, remains of the Khazar population were documented until the 13th century, and the name "Khazaria" even became established for the Crimean peninsula in the late Middle Ages. The memory of the “Jewish” empire on the Volga also remained alive in medieval Jewish literature, for example in the already mentioned work “Sefer ha-Kusari” by the important Sephardic philosopher and poet Yehuda ha-Levi. However, the continued existence of Khazarian Judaism and its role in the emergence of Judaism in Eastern Europe are questionable. As mentioned, Judaism was probably mainly spread among the Khazar elite, while the majority of the population was attached to the old religion, Christianity and, especially after the defeat in 965/969, Islam. Also, the source evidence hardly allows for the construction of a continuity of Judaism in Eastern Europe from the Khazars to the Ashkenazim, who emigrated to Eastern Europe especially from France and Germany in the late Middle Ages. Nevertheless, various authors, such as the Hungarian-Jewish author Arthur Koestler (1905–1983) in his book “The Thirteenth Tribe”, published in 1976, attempted to postulate the Khazars as ancestors of the Ashkenazim and thus as the ancestors of a large part of today's Jewish population. Recently, methods of modern genetics have also been used, but - in contrast to the claims of a small number of scholars - the majority of studies, especially also the most recent ones, do not document any genetic link of Ashkenazi Jews and earlier populations from the Khazar-ruled territories.
Cover page of the book “The thirteenth Tribe” by Arthur Koestler, published in 1976
The existence of a medieval Jewish empire in Eastern Europe was also exploited by anti-Semitic circles and the Nazis, considering the Soviet Union as the product of "Jewish Bolshevism", the heir to this "Jewish-barbaric Eastern Empire" and Russia as the "true home of Judaism" . The book “Attila's grandson on David's throne” by Erwin Soratroi from 1992 bumps into a similar horn; he wants to see "Eastern Jewry" in its entirety as the descendants of the "Hunnic" Khazars in order to de-legitimize the existence of the state of Israel: "This clarification about the ethnic origin of the Eastern Jews is of enormous importance, because currently the Semitic Jews are only 10 Percent, but the eastern Jewish Khazar descendants make up 90 percent of the world's Jewish population and also in what is now Israel. But this also destroys the basis of most of today's Israelis for their claim to the land of the Arabs and Jerusalem.” Because of its also otherwise anti-Semitic statements, Soratroi's book was banned in Germany.
Russian and Soviet historiography also attempted to downplay the role of the Khazars in the founding of Kiev or the foundation of medieval Russia ; rather, the Jewish Khazars were seen as the forerunners of the "Tatar (Muslim) yoke" that the Mongols would have brought from the steppes over the Eastern Slavs. When Mikhail Ilarionovič Artamonov (1898–1972), the excavator of Sarkel, wanted to demonstrate the significance of the Khazars in a book, he was condemned in 1951 by the Communist party newspaper “Pravda”. According to official Soviet historiography, the resistance of the Eastern Slavs against the "capitalist Jewish exploiters" in Itil led to the unification under the throne of Kiev and the emergence of the Russian state. Today's Russian historiography also struggles with the Khazars and a fair assessment of their historical importance. In Russian nationalist circles, the Khazar Empire, interpreted as the beginning of a Jewish conspiracy against Russia that continues to this day, has even become a central issue. This also makes the context of the above-mentioned debate about the Svjatoslav monument clearer.  Nevertheless, there is also a significant number of Russian scholars and archaeologists doing most important work on the Khazar heritage.
It is probably the relative uniqueness of the Khazar Empire as a large medieval state with a Jewish elite that makes its instrumentalization for various ideologies so tempting to the present day. This often obscures the objective view on one of the most exciting episodes in Europe's medieval history.
Note: This is the English translation of a paper published in German in the journal Religionen unterwegs 22/1 (March 2016), see: www.academia.edu/23552485/The_Religion_of_the_Khazars_-_a_Jewish_Empire_in_German_
1 https://www.fjc.ru/news/newsArticle.asp?AID=329123 and https://www.xeno.sova-center.ru/6BA2468/6BB4208/706B4D8?print=on
2 Movses Kałankatwacʽi II, 40: 240–241; transl. Dowsett 156
3 Wasserstein, The Khazars and the World of Islam 375–376; Howard-Johnston, Byzantine Sources for Khazar History 167; Golden, Khazar Studies I, 62–64; ders., The Conversion of the Khazars to Judaism 137; Shapira, Armenian and Georgian Sources on the Khazars 308–309, 349.
4 Noonan, Some Observations on the Economy of the Khazar Chaganate 211.
5 An English translation in: J. Marcus, The Jews in the Medieval World: A Sourcebook, 315–1791. New York 1938, 227–232; cf. also Brook, The Jews of Khazaria 98–100.
6 P. K. Kokovcov, Evrejsko-chazarskaja perepiska v X v. Leningrad 1932
7 N. Golb – O. Pritsak, Khazarian Hebrew Documents of the Tenth Century. London 1982.
8 Zuckerman, On the Date of the Khazars‛ Conversion to Judaism 246; Brook, The Jews of Khazaria 94–107.
9 Zuckerman, On the Date of the Khazars‛ Conversion to Judaism 246.
10 Golden, The Conversion of the Khazars to Judaism 156; Noonan, Some Observations on the Economy of the Khazar Chaganate 233–240; Brook, The Jews of Khazaria 107–108.
11 Vita Constantini IX (ed. Grives – Tomšič; transl. Bujnoch 73–74).
12 Golden, The Conversion of the Khazars to Judaism 130
13 Cited after Brook, The Jews of Khazaria 94–95.
14 Golden, The Conversion of the Khazars to Judaism 142 and 142; Brook, The Jews of Khazaria 110.
15 Golden, The Conversion of the Khazars to Judaism 144; Brook, The Jews of Khazaria 110.
16 Cited after Golden, Khazar Studies I, 97.
17 N. Golb – O. Pritsak, Khazarian Hebrew Documents of the Tenth Century. London 1982; cf. also Brook, The Jews of Khazaria 103–106.
18 Patrologia Latina 106, col. 1456; Zuckerman, On the Date of the Khazars‛ Conversion to Judaism 245, fn. 31; Golden, The Conversion of the Khazars to Judaism 139; Brook, The Jews of Khazaria 96.
19 Nicholas I, Patriarch of Constantinople, Letters (ed. Jenkins –Westerink), Nr. 106, 14–19 (p. 390).
20 Zuckerman, The Khazars and Byzantium 400; Zuckerman, On the Date of the Khazars‛ Conversion to Judaism 255
21 Dölger – Müller – Beihammer, Regesten Nr. 624; al-Mas‛ūdī cited after Golden, The Conversion of the Khazars to Judaism 144; Zuckerman, The Khazars and Byzantium 400; Zuckerman, On the Date of the Khazars‛ Conversion to Judaism 255; Brook, The Jews of Khazaria 90–91, 110; Roth, Chasaren 169.
22 Constantine Porphyrogenitus, De administrando imperio (ed. Moravcsik – Jenkins), c. 10–12: 62–64; Soustal – Belke, Die Byzantiner und ihre Nachbarn 86–88.
23 A. Koestler, Der dreizehnte Stamm. Das Reich der Khasaren und sein Erbe. Bergisch Gladbach 1989, 126–184; Golden, Khazar Studies: Achievements and Perspectives 9; Brook, The Jews of Khazaria 197–246. For an update on Genetic data see (with many thanks to Kevin Brook for the information): www.khazaria.com/genetics/medieval/khazars.html
24 E. Soratroi, Attilas Enkel auf Davids Thron. Chasaren, Ostjuden, Israeliten. Tübingen 1992, 56; cf. Also Roth, Chasaren 204–205; Th. Schirrmacher, Die osteuropäischen Juden – Nachfahren der mittelalterlichen Khasaren? Martin Buber Seminar Texte 23 (2004), see https://www.contra-mundum.org/schirrmacher/ mbstexte023.pdf.
25 Th. S. Noonan, The Khazar Qaghanate and its Impact on the Early Rus' State: The translatio imperii from Itil to Kiev, in: A. M. Khazanow – A. Wink (eds.), Nomads in the Sedentary World. Richmond 2001, 76–102.
26 Golden, Khazar Studies: Achievements and Perspectives 8, 19–28; V. A. Shnirelman, The Story of a Euphemism: The Khazars in Russian Nationalist Literature, in: P. B. Golden – H. Ben-Shammai – A. Róna-Tas (eds.), The World of the Khazars. New Perspectives. Leiden – Boston 2007, 353–372; Roth, Chasaren 205–208.
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