The Khazars, members of a confederation of Turkic-speaking tribes, are in contact with the Persians in the early seventh century. (The origin of the term Khazar and the early history of the Khazar people are obscure, but it is likely that the Khazars were originally located in the northern Caucasus region and were part of the western Turkic empire in present Turkestan).

The tribes constituting the Khazar union are, according to the most widely approved view, basically Turkic groups, such as the Oğuric peoples, including Šarağurs, Oğurs, Onoğurs, and Bulğars, who formed part of the Tiĕlè confederation.

These tribes, many driven out of their homelands by the Sabirs, who in turn fled the Asian Avars, had begun to flow into the Volga-Caspian-Pontic zone from as early as the fourth century CE and are recorded by Priscus to reside in the Western Eurasian steppelands as early as 463.

They appear to stem from Mongolia and South Siberia in the aftermath of the fall of the Hunnic/Xiōngnú nomadic polities.

A variegated tribal federation led by these Tűrks, probably comprising a complex assortment of Iranian, proto-Mongolic, Uralic, and Paleo-Siberian clans, had vanquished the Rouran Khaganate of the hegemonic central Asian Avars in 552 and swept westwards, taking in their train other steppe nomads and peoples from the Sogdian kingdom.

The Khazars have by about 630 become independent of the Turkic empire to the east.

…the khan of the Khazars, with whom the Heraclians have long had close ties of friendship.

Shortly after Justinian's marriage to the khan's sister, however, the khan is bribed by Tiberius to kill Justinian.

Forewarned by his wife, Justinian flees to the Bulgar kingdom.

The Khazars and Arabs fight each other directly in Armenia in the 720s, and, though victory passes repeatedly from one side to the other, Arab counterattacks eventually compel the Khazars to permanently withdraw north of the Caucasus.

(The Khazars' initial victories have the effect of permanently blocking Arab expansion northward into eastern Europe.)

The prominence and influence of the Khazar state continues to be reflected in its close relations with the Roman emperors.

The future emperor Constantine V takes a Khazar wife in 732, as had Justinian II in 704.

The Khazar Khaganate at its height is an immense and powerful state.

The Khazaria heartland is the lower Volga and the Caspian coast as far south as Derbent.

Khazar dominion over most of the Crimea and the northeast littoral of the Black Sea dates from the late seventh century.

By 800, Khazar holdings included most of the Pontic steppe as far west as the Dnieper River and as far east as the Aral Sea (some Turkic history atlases show the Khazar sphere of influence extending well east of the Aral).

During the Arab–Khazar war of the early eighth century, some Khazars had evacuated to the foothills of the Ural Mountains, and some settlements may have remained.

For a century and a half, the Khazars have ruled the southern half of Eastern Europe and present a bulwark blocking the Ural-Caspian gateway from Asia into Europe, while serving as a major artery of commerce between northern Europe and southwestern Asia along the Silk Road.

Their territory comprises much of modern-day southern European Russia, western Kazakhstan, eastern Ukraine, Azerbaijan, large portions of the northern Caucasus (Circassia, Dagestan), parts of Georgia, the Crimea, and northeastern Turkey.

Various place names invoking Khazar persist today.

The Caspian Sea, traditionally known as the Hyrcanian Sea and Mazandaran Sea in Persian, is still known to Muslims as the 'Khazar Sea' (Bahr ul-Khazar).

Many other cultures still use the name "Khazar Sea".

In Hungary, there are villages (and people with family names) called Kozár and Kazár.

At the peak of their empire, the Khazar permanent standing army may have numbered as many as one hundred thousand, controlling or exacting tribute from thirty different nations and tribes inhabiting the vast territories between the Caucasus, the Aral Sea, the Ural Mountains, and the Ukrainian steppes.

Khazar armies were led by the Khagan Bek and commanded by subordinate officers known as tarkhans.

When the bek sent out a body of troops, they would not retreat under any circumstances.

If they were defeated, every one who returned was killed.

Bulan was a Khazar king who led the conversion of the Khazars to Judaism.

The date of his reign is unknown, as the date of the conversion is hotly disputed, though it is certain that Bulan reigned some time between the mid-700s and the mid-800s.

Nor is it settled whether Bulan was the Bek or the Khagan of the Khazars.

D. M. Dunlop was certain that Bulan was a Khagan; however, more recent works, such as The Jews of Khazaria by Kevin Brook, assume that he was the Bek due to references to him leading military campaigns.

Khazar tradition held that before his own conversion, Bulan was religiously unaffiliated.

In his quest to discover which of the three Abrahamic religions would shape his own religious beliefs, he invited representatives from each to explain their fundamental tenets.

In the end, he chose Judaism.

The Khazar royalty and nobility had converted to Judaism at some point in the last decades of the eighth century or the early ninth century, and part of the general population had followed; to what extent is debated.

Concerning the Khazars, Christian of Stavelot writes in Expositio in Matthaeum Evangelistam 9864), “...in the lands of Gog and Magog who are a Hunnish race and call themselves Gazari there is one tribe, a very belligerent one—Alexander enclosed them and they escaped—and all of them profess the Jewish faith in its entirety.” Some researchers have suggested part of the reason for this mass conversion was political expediency to maintain a degree of neutrality: the Khazar empire is between growing populations, Muslims to the east and Christians to the west.

Both religions recognize Judaism as a forebear and worthy of some respect.

The exact date of the conversion is hotly contested.

It may have occurred as early as 740 or as late as the mid 800s.

Recently discovered numismatic evidence suggests that Judaism was the established state religion by around 830, and though St. Cyril (who visited Khazaria in 861) did not identify the Khazars as Jews, the khagan of that period, Zachariah, had a biblical Hebrew name.

A Persian work, Denkart, represents Judaism as the principal religion of the Khazars.

In the capital city, the Khazars establish a supreme court composed of seven members, and every major religion (Christianity, Islam, Judaism, and Slavic paganism) is represented on this judicial panel.

The Khazars thus sponsor religious tolerance in a time when surrounding countries persecute those who refuse to follow the faith of the rulers.

Income that is derived from duties on goods passing through Khazar territory, in addition to tribute paid by subordinate tribes, maintains the wealth and the strength of the Jewish Khazar empire throughout the ninth century.

In about 889, the Khazars and the Oguz, a confederation of Turkic peoples of the central Asian steppes, attack the nomadic Turkic Pechenegs, who had originally inhabited the area between the Volga and Yaik (Ural) rivers.

The Khazar Empire, faced with the growing might of the Pechenegs to their north and west and of the Russians around Kiev, suffers decline by the tenth century.

As the Khazar state can no longer impede the migration, the Pechenegs move westward, driving the Magyars into the Carpathian Basin and attacking Russian territory.

Ahmad ibn Fadlan is sent from Baghdad to the king of the Volga Bulgars, on behalf of the Abbasid Caliph al-Muqtadir.

Primarily, the purpose of the embassy is to explain Islamic law to the recently converted Bulgar peoples living on the eastern bank of the Volga River in what is now Russia.

(These are the Volga Bulgars; another group of Bulgars had moved westward in the sixth century, invading the country that today bears their name, and become Christians.).

Additionally, the embassy is sent in response to a request by the king of the Volga Bulgars to help them against their enemies, the Khazars.

Ibn Fadlan serves as the group's religious advisor and lead counselor for Islamic religious doctrine and law.

Ibn Fadlan and the diplomatic party utilize have established caravan routes toward Bukhara, now part of Uzbekistan, but instead of following that route all the way to the east, they had turned northward in what is now northeastern Iran.

Leaving the city of Gurgan near the Caspian Sea, they have crossed lands belonging to a variety of Turkic peoples.

One notable group he has encountered are the Khazars, a uniquely religious khanate that is one of the few peoples to adopt Judaism amid the surrounding Christian and Muslim spheres of influences.

Ahmad ibn Fadlan, in his travelogue, circa 922, had written “The Khazars and their king are all Jews”.Persian historian and geographer Ibn al-Faqih, writes in his famous Mukhtasar Kitab al-Buldan ("Concise Book of Lands"), circa 930, “All of the Khazars are Jews.

But they have been Judaized recently.”

Sviatoslav subsequently (probably in 968 or 969) destroys the Khazar capital of Atil.

A visitor to Atil wrote soon after Sviatoslav's campaign: "The Rus attacked, and no grape or raisin remained, not a leaf on a branch." (The exact chronology of his Khazar campaign is uncertain and disputed; for example, Mikhail Artamonov and David Christian proposed that the sack of Sarkel came after the destruction of Atil.)