Establishment of Buddhist Kingdoms by the Uighurs

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The Kyrgyz Conquest of Mongolia

The Kyrgyz (Kirghiz) were originally a Mongolian people from the mountain forests of the present-day Altai and Tuva districts of southern Siberia north of Dzungaria. Some of their tribes also lived in the western reaches of the Tianshan Range to Dzungaria’s south. The Eastern Turk Empire had included the traditional Kyrgyz Altai lands and, when the Uighurs took over that empire, the Uighurs conquered and devastated them in 758. Thereafter, the Kyrgyz and Uighurs remained ever enemies. Many Kyrgyz shifted to the western Tianshan area, where they allied themselves with the Qarluqs, Tibetans, and Abbasids against the Uighurs and Tang China.

Since the second half of the eighth century, Tibetan-Arab trade had passed from western Tibet through the Wakhan Corridor to western Bactria and on to Sogdia. A second route, however, passed from northeastern Tibet, through the Tibetan holdings in the Gansu Corridor, to the crucial areas of Turfan and Beshbaliq, disputed by the Tibetans, Uighurs and Tang China until settled in favor of the Tibetans in 821. It then continued across southern Dzungaria, over the western spur of the Tianshan Mountains to northern West Turkistan, all of which was held by the Qarluqs until the 790s and then the Uighurs, and finally on to Arab-held Sogdia. Uighur bandits constantly plagued the portion of the route that passed through the Tianshan Mountains. The Kyrgyz played an important role in fighting these bandits and keeping the trade route open and safe.

Map 19: Tibetan-Arab Trade Routes
Map 19: Tibetan-Arab Trade Routes

The Tibetan merchants on this route were Buddhists, as evidenced by the Buddhist mantras (sacred syllables) they carved in Tibetan script on rocks found near Lake Issyk Kul in modern-day eastern Kyrgyzstan. They were not subject to religious persecution or restrictions in the Muslim lands at the western terminus of the Central Asian Silk Route, otherwise they would not have risked the journey. This is another indication that the 815 jihad by Caliph al-Ma'mun against the Tibetan-Turki Shahi-Qarluq-Oghuz alliance was directed at political objectives, not at a mass, forced conversion of people viewed as infidels.

After the peace treaties with the Tibetans and Tang China in 821, the Uighurs gradually became weakened by internal discord and the difficulties imposed by the Tibetan wedge dividing their territories in Mongolia and Dzungaria. In 840, after a particularly severe winter of heavy snowfall had decimated the Uighur herds, the Kyrgyz overthrew the Orkhon Empire in Mongolia, Dzungaria, and the eastern portion of northern West Turkistan. The Kyrgyz then ruled the area from their base in the Altai Mountains until they themselves were displaced by the Khitans (Kitan) in 924.

The Uighur Migration into Turkistan and the Gansu Corridor

With the Kyrgyz takeover of their empire, the majority of the Orkhon Uighurs migrated southward. Most went to Turfan (Qocho), Beshbaliq, and Kucha. These city-states along or adjacent to the northern rim of the Tarim Basin with Tocharian culture and large Sogdian and Han Chinese minorities were their natural destination.

The Uighurs had maintained a small presence in Turfan since at least the fourth century CE and had ruled it briefly between 605 and the 630s. They had controlled both it and Beshbaliq periodically between the 790s and 821. They now had a peace treaty with the Tibetans who were currently ruling the two city-states. Furthermore, they had a presence in Kucha since the 790s after having taken it from Tang China.

Kucha was also disputed by the Qarluqs from Kashgar and the Tibetans from Turfan, and it is unclear who was actually governing it at this time. However, even if it had been the Qarluqs, the latter were still the nominal vassals of the Uighurs, despite their almost incessant battles against them over the last century. The Uighurs would neither have been evicted by the Qarluqs nor denied further entry. Thus, with long familiarity with the sedentary urban culture of these oasis states, it was not difficult for the Uighur refugees to move there and make the transition from nomadic steppe life.

There were three other smaller bands of Orkhon Uighurs who did not settle in these northern Tarim city-states. The largest of the three migrated to the city-states of the Gansu Corridor, ruled by the Tibetans, and later became known as the Yellow Yugurs. Of the other two, one migrated to the west from the Uighur-held eastern portion of northern West Turkistan and settled among the Qarluqs in the Chu River Valley in northern Kyrgyzstan. Another settled among the Qarluqs in Kashgar. A minor group went east to Manchuria, quickly assimilated and does not appear mentioned in histories again.

Map 20: Dispersion of the Orkhon Uighurs from Mongolia and Dzungaria
Map 20: Dispersion of the Orkhon Uighurs from Mongolia and Dzungaria

All four groups of Uighurs adopted Buddhism after migration. Those on the northern rim of the Tarim Basin adopted the Tocharian/Sogdian/Han Chinese form of Turfan and Kucha, those in the Gansu Corridor a Han Chinese/Tibetan blend, those in the Chu Valley the West Turkistani Sogdian style, while those in Kashgar the Kashgari form. Except for the Yellow Yugurs, all the other Uighur branches eventually converted centuries later to Islam. To understand better the dynamics of conversion among the Turks, let us once more examine the reasons for the Uighur change of religion, this time from Manichaeism to Buddhism. We shall focus our discussion on the two largest groups, the Qocho (Qoco) Uighurs and Yellow Yugurs.

Previous Uighur Familiarity with Buddhism

Before the conversion of the Orkhon Uighur nobility to Manichaeism, the Uighurs had previously adopted Buddhism when they had ruled Turfan during the early seventh century. The Uighur warriors and common people had maintained a certain level of devotion to Buddhism throughout the period of the Uighur Orkhon Empire. This is evidenced by the anti-Buddhist rhetoric of some of the later Uighur qaghans. Nevertheless, the Uighur Manichaean texts of this period contained strong Buddhist elements due to the background of the Sogdian translators. Furthermore, the Uighur aristocracy itself had not been exclusively Manichaean. Many also followed the Nestorian Christian faith. Some even accepted Buddhism, as evidenced by the Tibetan emperor, Tri Relpachen, having commissioned several translations of Buddhist texts from Tibetan into Uighur shortly after the peace treaty of 821. However, there were reasons other than familiarity that undoubtedly contributed to the Uighurs’ change of religions.

The Breakup of the Tibetan Empire

In 836, four years before the Kyrgyz takeover of the Orkhon Uighur realm, Emperor Relpachen of Tibet was assassinated by his brother, Langdarma (gLang-dar-ma, r. 836 – 842). Assuming the throne, the new emperor instituted a severe repression of Buddhism throughout Tibet. It was aimed at ending the Religious Council’s interference in politics and the drain on the economy made by Tri Relpachen’s policy of legislating ever more grandiose public support of the monasteries. Langdarma closed all the monasteries and forced the monks to disrobe. He did not physically destroy these complexes, however, or their libraries. Even without access to the scriptural literature, Buddhism continued among many Tibetan lay practitioners.

In 842, Langdarma was assassinated by a monk who, according to one scholar, was the deposed head of the Religious Council and former abbot of Samyay. Civil war ensued over succession to the throne, resulting in the breakup of the Tibetan Empire. Over the next two decades, Tibet gradually withdrew from its holdings in Gansu and East Turkistan. Some became independent political entities – first Dunhuang, which became known as the state of Guiyijun (Kuei i-chün, 848 – 890s) governed by a local Han Chinese clan, and then Khotan (851 – 1006) ruled by its own, unbroken royal line. In others, local Han Chinese took initial control but did not establish a strong rule, for instance Turfan, starting in 851. By 866, however, the Uighur immigrant communities in these former Tibetan holdings had become strong enough to establish their own rule.

The Subsequent Political Division of East Turkistan and Gansu

The Qocho Uighur Kingdom (866 – 1209) at first included the area between Turfan and Beshbaliq. Eventually it spanned the northern rim of the Tarim Basin as far as Kucha. The eastern portion of the southern rim up to the borders of Khotan became no-man’s land, with a few Tibetan tribes staying behind. Trade through it between Han China and Khotan and then on to the west came to a standstill. Kashgar remained in Qarluq hands.

Map 21: Central Asia, Mid-Ninth Century
Map 21: Central Asia, Mid-Ninth Century

The Yellow Yugur Kingdom (866 – 1028) occupied the Gansu Corridor. Guiyijun helped the immigrant Uighurs establish it through military aid to expel the remaining remnants of Tibetan rule. Many Tibetans fled south to the Kokonor region where most had originated and where eventually the Tsongka (Tsong-kha) Kingdom arose. The Yellow Yugurs soon turned on their allies in Guiyijun, taking it over in the 890s.

One further group of people, the Tanguts, lived in the area and soon became a major force in the historical development. They were related to the Tibetans and their territory in eastern Gansu separated the Yellow Yugurs from the Han Chinese at Chang’an. In the mid-seventh century, the Tanguts had fled their homeland in the Kokonor region due to constant attacks by central Tibet and had taken refuge in eastern Gansu under Tang protection. There they met with Buddhism for the first time. Their ranks were swelled a century later by further Tangut refugees fleeing Tibetan military activity in the region after the An Lushan rebellion.

All these areas of Gansu and East Turkistan to which Tibetan culture had spread were spared Langdarma’s repression of Buddhism. Many Tibetan Buddhist refugees, in fact, sought asylum there and thus Buddhism was flourishing in these regions when the Orkhon Uighurs arrived. Han Chinese-style Buddhism, however, was the major form but with strong Tibetan influences and, in Turfan, large doses of Sogdian and Tocharian elements.

The Repression of Buddhism in Han China

Meanwhile, Buddhism was suffering an even worse persecution in Han China than in Tibet. During the century after the Tang emperor, Xuanzong’s, reforms to curb Buddhist power, the Han Chinese Buddhist monasteries had again received tax exempt status. They held a disproportionate share of the nation’s wealth, particularly precious metals used for temple images, and employed a large number of laypeople on the vast estates they owned. The ladies and eunuchs of the imperial harem were extremely devoted to the monks and nuns, and influenced the emperors to indulge these excesses.

When Emperor Wuzong (Wu-tsung, r. 841 – 847) ascended the throne, the Daoist court officials persuaded him to overthrow the previous emperor’s policy toward the Buddhist monasteries. Prompted by these officials’ jealous anxiety over the imperial harem’s influence on policy and by their concern for the national economy, Wuzong took action. In 841, he ordered all monks who kept women and preyed on the superstitions of the people to be disrobed and all excess money and real estate owned by the monasteries confiscated. In so doing, he was fulfilling the traditional role of northern Han Chinese emperors as protectors of the purity of the Buddhist doctrine.

The Daoist ministers, however, were not satisfied with the Emperor’s move. They called for the removal of all foreign influences in Han China and a return to traditional values and ethics. Identifying not only Manichaeism and Nestorian Christianity, but also Buddhism as foreign religions, they moved first against the former two, as they were present in Han China on a more limited scale. In 843, they influenced the Emperor to impose a total ban on Manichaeism and Nestorian Christianity throughout the empire and evict all its clerics. This affected not only the Sogdian merchant community, but also any Uighur nobility that might seek refuge in Han China. In 845, the Daoist faction convinced the Emperor to destroy all but a few Buddhist temples and monasteries, confiscate and melt down their images made of precious metals, return all monks and nuns to lay life, dismiss all laypersons in service on monastic land, and appropriate all monastic-owned property.

Analysis of the Repression

It is noteworthy that this persecution and ban on foreign religions was never extended to Islam. The Muslim merchant community was limited to the coastal cities of the Southeast. They did not ply the Silk Route until centuries later. The Sogdians, Han Chinese, and Tibetans carried out that trade, with the Uighurs eager to gain a share. The competition was fierce and the fact that the Daoist ministers’ severity was directed not only at the Buddhists, but against the Manichaeans and Nestorian Christians as well, indicates that they were primarily motivated by economic concerns.

Tibet was in the throws of a civil war and clearly about to lose its hold over Gansu and East Turkistan. The only rivals left for the power vacuum the Tibetans would leave on the Silk Route were the Uighurs and the Sogdians. The fact that the persecution was directed only at religions held by the Sogdians, Han Chinese, Tibetans, and Uighurs, and not by the Arabs or Persians, confirms that the focus of the Tang ministers’ policy was the Silk Route and Central Asia, not the South Seas. If religious persecution in Central Asia was not being implemented for political reasons, it was for economic concerns, and hardly ever on spiritual or doctrinal grounds.


Upon the death of Wuzong in 847, the new emperor, Xuanzong (Hsüan-tsung, r. 847 – 860), executed the Daoist leaders and soon gave permission for the restoration of Buddhism. Most of the Han Chinese Buddhist sects, however, could not survive this severe persecution. Only the Chan (Jap. Zen) and Pure Land schools recovered, the former because of its location in the more remote mountainous areas of western Han China and its lack of dependency on monastic libraries, and the latter because of its popular, nonscholarly base.

As the Tang Dynasty withered in power until its end in 907 and Han China split apart during the Five Dynasties Period (907 – 960), the Han Chinese lost all effective influence in Central Asia. The strategy of the Daoist ministers for eliminating competition on the Silk Route and gaining economic advantage for Tang China ended in failure.

Effects of These Developments on the Uighurs’ Conversion to Buddhism

This was the political and economic context, then, within which the Orkhon Uighurs changed religions from Manichaeism to Buddhism. As with the Eastern Turk shift from shamanism to Buddhism and back, and the earlier conversion of the Uighurs from shamanism to Buddhism and then Manichaeism, three factors primarily influenced the change and choice of religion. First was the need for a unifying force to rally the people behind a new dynasty. Second was the search for supernatural power to support the new rule, based on evaluating the success of various religions in propping up other foreign regimes. Third was the overriding priority of gaining economic benefit from controlling the Silk Route trade.

The Qocho Uighurs and Yellow Yugurs were starting not only new dynasties, but also new ways of life as sedentary urban dwellers of oases. Manichaeism had proven bankrupt as a state religion capable of providing the supernatural power to sustain their previous Orkhon Empire. They needed a new religion around which to rally and to provide them with the extraworldly support needed to make the transition successfully.

The Tibetan Empire had just collapsed and Tang China was on the eve of disintegration. The Uighurs had previously fought against both and knew their strengths and weaknesses. From a nomadic, shamanic point of view, the failure of both could only be attributed to their recent persecution of Buddhism. The Tibetans and Tang China had both offended the Buddhist deities and had lost their support. The supernatural power of Buddhism was clearly proven. A century earlier the Uighurs had decided that the defeats of the Tang emperor by the Abbasids and the An Lushan rebellion had been due to the weakness of Buddhism and so had discarded that faith themselves in favor of Manichaeism. However, the course of events had shown that their evaluation had been mistaken.

Furthermore, both Tibet and Tang China were now cut off from the Silk Route and too weak to control its lucrative trade, which was still mostly in the hands of the Sogdians. Many central Tibetan and Han Chinese Buddhist refugees, fleeing persecution in their own lands, were flocking to the territories through which the eastern part of the Silk Route passed, namely Turfan, Guiyijun, the Gansu Corridor, the Kokonor region of northeastern Tibet, and the Tangut realm. This was because Buddhism continued to flourish in all these areas without government hindrance. Thus, Buddhism was undoubtedly stronger along the eastern portion of the Silk Route than Manichaeism or Nestorian Christianity was. In addition, as both Tibet and Tang China had just ended periods of repression of Buddhism, those who followed this faith along the Silk Route were without a strong royal patron. The monastics and laypeople would equally welcome a religious ruler who would assume this role.

Therefore, since Buddhism was so well-established and stable in East Turkistan and Gansu, among not only the Sogdians, but the other Central Asian peoples in the region as well, and since many Uighurs were already familiar with it, particularly those already living in these areas, Buddhism was the logical choice of religion for the Qocho Uighur and Yellow Yugur princes. Becoming the upholders of Buddhism would put them in the strongest position to be accepted as lords and protectors of the Silk Route. The rulers of both kingdoms, therefore, assumed the title “bodhisattva prince,” as previous Uighur rulers had done a century and a half earlier when they had formerly controlled Turfan.

With the help of the multilingual Sogdians, the Uighurs now began translating the Buddhist scriptures into their language, not from Sogdian editions, however, but from Han Chinese and Tocharian texts, borrowing elements from previous Old Turk translations. The Sogdians did not translate from their own texts perhaps because they wished to maintain their unique cultural identity and not become lost in a Uighur Buddhist culture in which everyone followed the same scriptural tradition.

The Position of Islam at the End of the Early Abbasid Period

In the mid-ninth century when the Abbasid caliphate was beginning to lose its direct hold on Central Asia, Islam was still mostly limited there to Sogdia. It was found among the Arab descendants and the local population who had accepted the faith not out of force, but mostly due to the attraction of Islamic high culture. When the Abbasids had led jihads against Saurashtra and Kabul, although their opponents were Buddhists, their holy wars had not been aimed at destroying Buddhism per se. In both cases, the Muslim leaders had confused the upholders of Buddhism with the anti-Abbasid Musalemiyya and Manichaean Shiite rebels. For the most part, the Abbasids were tolerant of Buddhism and maintained trade and cultural relations with Buddhist countries.

In the following decades a major shift occurred as Central Asia came under the rule of various Turkic peoples. Several of the Turkic states adopted Islam because their leaders had been slave military chiefs under the Abbasids and had won their freedom by converting to Islam. One of them, however, the Qarakhanid state, voluntarily accepted Islam for many of the same reasons that previous Turkic peoples, such as the Eastern Turks and Uighurs, had earlier changed religions and adopted Buddhism, shamanism, or Manichaeism. Foremost on the minds of these Turkic rulers were issues of supernatural power to support their state and geopolitical strategies for gaining control of the Silk Route trade. The further spread of Islam into Central Asia and India and its interaction with Buddhism in both these regions will become more understandable within that context.