These colonies were frequently visited by Christian missionaries, who endeavored to convert the native population to their faith, and incidentally also to win over the Jews. The Patriarchs of Constantinople were then hopeful of drawing the people of the Old Testament into the fold of the New. The Patriarch Photius, of the ninth century, writes thus to the Bishop of Bosporus (Kerch): "Wert thou also to capture the Judeans there, securing their obedience unto Christ, I should welcome with my whole soul the fruits of such beautiful hopes." The "Judeans," however, not only did not take the bait of the missionaries, but even managed to spoil their propaganda among the pagans. The most illustrious of all Byzantine missionaries, Cyril and Methodius, had frequent occasion to quarrel with "the Judeans, who blaspheme the Christian faith," and the boastful ecclesiastic legend asserts that the holy brothers "by prayer and eloquence defeated the Judeans [in disputes] and put them to shame" (about 860).

The struggle between the Christian missionaries and the Jews during that period had for its object the Khazar nation, part of whom had embraced Judaism.

2. The Kingdom of the Khazars

While Byzantium was pressing on the Euxine colonies from the west, endeavoring to draw them, together with the adjoining lands of the Slavs, into the sphere of Christian civilization, a new power from the east, from the Caucasus and the Caspian region, came rushing along in the same direction. We refer to the Khazars, or Kazars.⁶ Forming originally a conglomerate of Finno-Turkish tribes, the warlike Khazars appeared in the Caucasus during the "migration of nations," and began to make inroads into the Persian Empire of the Sassanids, often acting as the tools of Persia's rival, Byzantium. The great Arabic conquests of the seventh century and the rise of the powerful Eastern Caliphate checked the movement of the Khazars towards the East, and turned it westward, to the shores of the Caspian Sea, the mouths of the Volga and the Don, the Byzantine colonies on the Black and Azov Seas, and, in particular, the flourishing region of Tauris. At the mouth of the Volga, where the mighty river joins the Caspian Sea, near the present city of Astrakhan, arose the kingdom of the Khazars with its capital Ityl, the name originally designating the river Volga. From there the bellicose Khazars made constant raids upon the Slavonian tribes far and near, to the very gates of Kiev, forcing them to become their tributaries.

Another Khazar center was established in the Crimea, among Byzantine Greeks and Jews. From the Crimea the Khazars pressed forward in the direction of Byzantium and the Balkan Peninsula, constituting a serious menace to the Roman Empire of the East. As a rule, the Byzantine emperors concluded alliances with the kings, or khagans, of the Khazars, checking their unbridled energy by means of concessions and the payment of tribute. In Constantinople the illusion was fostered that the Church, and with it Byzantine diplomacy, were in the end bound to triumph over all the Khazars – by converting them to Christianity. With this purpose in view, missionaries were dispatched from Byzantium, while the local bishops of Tauris were working zealously to the same end. But the task proved extremely difficult, for the Greek Church found itself face to face with a powerful rival in Judaism, which succeeded in establishing its hold on a part of the Khazar nation.

While yet in their pagan state, the Khazars were exposed at one and the same time to the influences of three religions: Mohammedanism, which pursued its triumphant march from the Arabic Caliphate; Christianity, which was spreading in Byzantium, and Judaism, which, headed by the Exilarchs and Gaons of Babylonia, was centered in the Caliphate, while its ramifications spread all over the Empire of Byzantium and its colonies on the Black Sea. The Arabs and the Byzantines succeeded in converting several groups of the Khazar population to Islam and Christianity, but the lion's share fell to Judaism, for it managed to get hold of the royal dynasty and the ruling classes.

The conversion of the Khazars to Judaism, which took place about 740, is described circumstantially in the traditions preserved among the Jews and in the accounts of the medieval Arabic travelers:

The King, or Khagan, of the Khazars, by the name of Bulan, had resolved to abandon paganism, but was undecided as to the religion he should adopt instead. Messengers sent by the Caliph persuaded him to accept Islam, envoys from Byzantium endeavored to win him over to Christianity, and representatives of Judaism championed their own faith. As a result, Bulan arranged a disputation between the advocates of the three religions, to be held in his presence, but he failed to carry away any definite conviction from their arguments and mutual refutations. Thereupon the King invited first the Christian and then the Mohammedan, and questioned them separately. On asking the former which religion he thought was the better of the two, Judaism or Mohammedanism, he received the reply: Judaism, since it is the older of the two, and the basis of all religions.⁷ On asking the Mohammedan, which religion he preferred, Judaism or Christianity, he received the same reply in favor of Judaism, with the same motivation. "If that be the case," Bulan argued in consequence, "if both the Mohammedan and the Christian acknowledge the superiority of Judaism to the religion of their antagonist, I too prefer to adopt the Jewish religion." Bulan accordingly embraced Judaism, and many of the Khazar nobles followed his example.

According to the Jewish sources, one of Bulan's descendants, the Khagan Obadiah, was a particularly zealous adherent of Judaism. He invited – possibly from Babylonia – many Jewish sages to his country, to instruct the converted Khazars in Bible and Talmud, and he founded synagogues, and established Divine services.

In the ninth and tenth centuries, the kingdom of the Khazars, governed by rulers professing the Jewish faith, attained to outward power and inner prosperity. The accounts of the Arabic writers of that period throw an interesting light on the inner life of the Khazars, which was marked by religious tolerance. The king of the Khazars and the governing classes professed the Jewish religion. Among the lower classes the three monotheistic religions were all represented, and in addition a considerable number of pagans still survived. In spite of the fact that royalty and nobility professed Judaism, the principle of religious equality was never violated. The khagan had under him seven (according to another version, nine) judges: two for the followers of the Jewish religion, two each for the Christians and Mohammedans, and one for the pagans – the Slavs, the Russians, and other races. Only occasionally did the Khazar king show signs of intolerance, particularly when rumors concerning Jewish persecutions in other countries came to his ears. Thus, on one occasion, about 921, on being informed that the Mohammedans had destroyed a synagogue somewhere in the land of Babunj, the Khagan gave orders to destroy the tower (minaret) of a certain mosque and to kill the muezzins (the heralds who call to prayer), explaining his attitude in these words: "I should have destroyed the mosque itself, had I not feared that not a single synagogue would be left standing in the lands of the Mohammedans."

In the kingdom of the Khazars, favorably situated as it was between the Caliphate of Bagdad and the Byzantine Empire, the Jews evidently played an important economic rôle. During the ninth and tenth centuries the territory of the Khazars was traversed by one of the great trade routes which connected the three parts of the Old World. According to the testimony of Ibn Khordadbeh, an Arabic geographer of the ninth century, Jewish merchants, who were able to speak the principal Asiatic and European languages, "traveled from West to East and from East to West, on sea and by land." The land route led from Persia and the Caucasus "through the country of the Slavs, near the capital of the Khazars" (the mouth of the Volga), by crossing the Sea of Jorjan (the Caspian Sea). Another Arabic writer, named Ibn Fakih,⁸ who wrote shortly after 900, testifies that on the route of the "Slav merchants," who were trading between the Sea of the Khazars (the Caspian Sea) and that of Rum (the Byzantine or Black Sea), was found the Jewish city of Samkers, on the Taman Peninsula, near the Crimea.⁹

During this period of prosperity the kingdom of the Khazars received a considerable Jewish influx from Byzantium, where the Jews were persecuted by Emperor Basil the Macedonian (867-886), being forcibly converted to Christianity, while hundreds of Jewish communities were devastated. The Jewish emigrants from Byzantium were naturally attracted towards a land in which Judaism was the religion of the Government and the Court, though equal toleration was accorded to all other religions. The well-known Arabic writer Masudi refers to this Jewish immigration in the following passage:

The population of the Khazar capital consists of Moslems, Christians, Jews, and pagans. The king, his court, and all members of the Khazar tribe profess the Jewish religion, which has been the dominant faith of the country since the time of the Caliph Harun ar-Rashid. Many Jews who settled among the Khazars came from all the cities of the Moslems and the lands of Rum (Byzantium), the reason being that the king of Rum persecuted the Jews of his empire in order to force them to adopt Christianity… In this way a large number of Jews left the land of Rum in order to depart to the Khazars.

This testimony dates from the year 954. Contemporaneous with it is the extremely interesting correspondence between Joseph, the Khagan of the Khazars, and Hasdai Ibn Shaprut, the Jewish statesman of the Cordova Caliphate in Spain. Being a high official at the court of Abderrahman III., Hasdai maintained diplomatic relations with the emperors of Byzantium and other rulers of Asia and Europe, and in this way came to learn of the Khazar kingdom, through the Persian and Byzantine ambassadors. The news of the existence of a land somewhere beyond the seas where a Jew sat on the throne, and Judaism was the religion of the state, filled Hasdai with joy. Firmly convinced that he had found the clue to the lost Jewish kingdom of which popular Jewish tradition had so much to tell, the Jewish statesman at the Moslem court felt the burning need of getting in touch with the rulers of Khazaria, and, in case the rumors should prove correct, of transferring his abode thither and devoting his powers of statesmanship to his fellow-Jews. Prolonged inquiries elicited the information that the land of the Khazars lay fifteen days by sea from Constantinople, that it stood in commercial relations with Byzantium, that the name of its present ruler was Joseph, and that the safest means of communicating with him was by way of Hungary, Bulgaria, and Russia. After several vain attempts to get in touch with the ruler of the Khazars Hasdai finally succeeded in having an elaborate Hebrew epistle delivered into the hands of King Joseph (about 955).

In his epistle Hasdai first gives an account of himself and his position at the court of Cordova, and then proceeds to beg the King of the Khazars to inform him in detail of the rise and present status of "the Jewish kingdom," being anxious to find out "whether there is anywhere a soil and a kingdom where scattered Israel is not subject and subordinate to others."

Were I to know – Hasdai continues – that this is true, I should renounce my place of honor, abandon my lofty rank, forsake my family, and wander over mountains and hills, by sea and on land, until I reached the dwelling-place of my lord and sovereign, there to behold his greatness and splendor, the seats of his subjects, the position of his servants, and the tranquillity of the remnant of Israel… Having been cast down from our former glory, and now living in exile, we are powerless to answer those who constantly say unto us: "Every nation hath its own kingdom, while you have no trace [of a kingdom] on earth." But when we received the news about our lord and sovereign, about the power of his kingdom and the multitude of his hosts, we were filled with astonishment. We lifted our heads, our spirit revived, and our hands were strengthened, the kingdom of my lord serving us as an answer. Would that this rumor might increase in strength [i. e. be verified], for thereby will our greatness be enhanced!

After long and painful waiting Hasdai received the King's reply. In it the ruler of the Khazars gives an account of the heterogeneous composition of his people and the various religions professed by it. He describes how King Bulan and his princes embraced the Jewish faith after testing the various rival creeds, and how zealously it was upheld by the Kings Obadiah, Hezekiah, Manasseh, Hanukkah, Isaac, Zebulun, Moses (or Manasseh II.), Nissi, Aaron, Menahem, Benjamin, Aaron (II.), the last being the father of the writer, King Joseph. The King continues:

I reside [i. e. my residence is situated] at the mouth of the river Ityl [Volga]; at the end of the river is found the Sea of Jorjan [the Caspian Sea]. The beginning of the river is towards the east, at a distance of a four months' journey. Along the banks of the river there are many nations living in towns and villages, in open as well as fortified places. These are their names: Burtas, Bulgar, Suvar, Arisu, Tzarmis, Venentit, Sever, Slaviun.¹⁰ Each of these nations is very numerous, and all of them are tributary to me. From there the boundary turns towards Buarezm [probably Khwarism], up to Jorjan, and all the inhabitants of the sea-shore, for a distance of one month's journey, are tributary to me. To the south are found Semender, Bak-Tadlud, up to the gates of Bab al-Abwab, which are situated on the coast.¹¹ … To the west there are Sarkel, Samkrtz, Kertz, Sugdai, Alus, Lambat, Bartnit, Alubika, Kut, Mankup, Budak, Alma, and Gruzin.¹² All these localities are situated on the shores of the Sea of Kostantinia¹³ towards the west… They are all tributary to me. Their dwellings and camping-places are scattered over a distance of a four months' journey.

Know and take notice that I live at the mouth of the river [Volga], and with the help of the Almighty I guard the entrance to this river, and prevent the Russians, who arrive in vessels, from passing into the Caspian Sea for the purpose of making their way to the Ishmaelites [Mohammedans]. In the same manner I keep the enemies on land from approaching the gates of Bab al-Abwab. Because of this I am at war with them, and were I to let them pass but once, they would destroy the whole land of the Ishmaelites as far as Bagdad… Our eyes are [turned] to God and to the wise men of Israel who preside over the academies of Jerusalem and Babylon. We are far away from Zion, but it has come to our ears that, on account of our sins, the calculations [concerning the coming of the Messiah] have become confused, so that we know nothing. May it please the Lord to act for the sake of His great Name. May the destruction of His temple, and the cutting off of the holy service, and the misfortunes that have befallen us, not appear small in His sight. May the words of the prophet be fulfilled: "And the Lord, whom ye seek, shall suddenly come to His temple" (Mal. iii. 1). We have nothing in our possession [concerning the coming of the Messiah] except the prophecy of Daniel. May the God of Israel hasten our redemption and gather together all our exiled and scattered [brethren] in my lifetime, in thy lifetime, and in the lifetime of the whole house of Israel, who love His name.

The concluding phrases cast a shadow of doubt on the authenticity of this epistle or, more correctly, of some parts of both epistles, which more probably reflect the mournful Messianic temper of the sixteenth century, when this correspondence was brought to light by Spanish exiles who had made their way to Constantinople, than the state of mind of a Spanish dignitary or a Khazar king of the tenth century. However, the essential data contained in Joseph's epistle are so completely in accord with the reports of contemporaneous Arabic writers that the substance of this correspondence may be safely declared to be authentic.¹⁴