The Initial Choice of Buddhism
The Uighurs used the same criterion for adapting foreign religions as did the Eastern Turks. They first chose Buddhism as their state religion when the Chinese Sui forces had helped them conquer Turfan in 605. They were apparently as impressed as the Eastern Turks had been by the Sui military success in unifying Han China under the spiritual protection of Buddhism. As the Sui founder styled himself a Buddhist universal emperor (Skt. chakravartin), both the Uighur and Eastern Turk leaders called themselves “bodhisattva princes.” However, also like the Eastern Turks, the Uighurs adopted primarily a Central Asian, not a Han Chinese form of Buddhism, to escape assimilation into Han Chinese culture. They basically followed the Tocharian/Khotanese form of Buddhism found in Turfan, blending it with traditional Turkic and some northern Chinese elements, as had done the Eastern Turks.
The Tang Dynasty (618 – 906) replaced the Sui only twenty-nine years of its rule. Although the early Tang emperors reinstated the Confucian examination system for government service and favored Daoism, they supported Buddhism as well. In fact, the Sui and early Tang periods were the highpoint for the development and spread of most of the Han Chinese Buddhist sects. Although the Eastern Turks saw Buddhism as responsible for the loss of their own first dynasty, the Uighurs of the time apparently did not see either the Sui capitulation to Tang China in 618 or their own loss of Turfan to the Tang forces, also in the 630s, as a fault of Buddhism. They remained loyal Tang allies and continued with Buddhism.
Doubts about Buddhism in Face of Developments in Tang China and Tibet
Since the time of the usurpation of the Tang Dynasty by Empress Wu between 684 and 705, Tang military power, although highly successful in many ways, had been continually undermined by Xuanzong’s inability to draft Buddhist monks into military service or tax the monasteries to help finance his campaigns. In 740, the Emperor had restricted the number of Han Chinese monks, expelled all foreign monastics from Tang China, and withdrawn tax exempt status from the monasteries. Despite these steps, the Tang forces were defeated on the Talas River in West Turkistan in 751 and, in 755, Xuanzong had been deposed by the An Lushan rebellion.
The Uighur ruler, Bogu Qaghan, in overthrowing the Eastern Turks in 744, had inherited the role of safekeeper of the Turks’ sacred mountain, Otukan. Consequently, his situation was completely different from that of previous Uighur leaders. Morally responsible now for all Turkic tribes, the Qaghan was undoubtedly aware of Tonyuquq’s criticism of Buddhism as leading to an inevitable loss of pan-Turkic martial values. This critique of Buddhism was doubly proven by the humiliating defeats of Xuanzong in West Turkistan and in his own capital, Chang’an. From a Turkic point of view, the Tang Emperor had obviously not gone far enough in eliminating the Buddhist source of his military weakness.
In addition, a few months before the An Lushan rebellion, the Tibetan emperor, Mey-agtsom, had been assassinated for his pro-Buddhist leanings. Tibet, the other main power in the region, was now in the midst of a period of suppression of Buddhism. Therefore, in choosing a religion to unify his people, Bogu Qaghan could not possibly take Buddhism and have any credibility as leader of all Turks. On the other hand, he was blocked from choosing the blend of Tengrism and Turkic shamanism as well, since that was the faith of the Eastern Turks whom he had defeated to gain his position. The traditional religion clearly had not had the power to sustain a militarily strong nation.
Reasons for Choosing Manichaeism: The Wish to Maintain Friendly Relations with Tang China
For a century and a half, the Uighurs had been more or less allies of Tang China. They had demonstrated their military superiority to the Tang forces by suppressing the An Lushan rebellion, when the latter had failed to do so. Nevertheless, the Uighur qaghans still wished, for the moment, to maintain friendly relations with Tang China. Despite the Uighurs’ sacking of Chang’an and Loyang, the Tang court wished the same.
In 713, the powerful Eastern Turk minister, Tonyuquq, had convinced Qapaghan Qaghan (r. 692 - 716) to deport the Sogdian community from Mongolia as he steered the empire toward a revival of its shamanic and Tengrian traditions. The community included both Buddhists and Manichaeans, and the Tang court had allowed them all to join with the Sogdians already settled in Chang’an and Loyang. In 732, however, Xuanzong had banned any Han Chinese from following Manichaeism and had restricted it to the foreign community. Eight years later, he had deported all foreign Buddhist monks, yet still tolerated aliens in Tang China who professed Manichaeism. If the Uighurs were to adopt this latter religion, they could maintain friendly relations with Tang China without offending its religious policies. There were additional reasons, however, for making this choice.
Economic Benefits and Geopolitics
The Uighurs were intent on further expansion of their territory, particularly into the Tarim Basin where they could control the lucrative Silk Route trade. Tang China had only a weak presence in Turfan, Beshbaliq, and along the northern branch of the route in Kucha and Kashgar. The Tibetans also had only a weak presence along the Silk Route’s southern branch. Sogdian merchants, however, were found in all the oasis city-states, primarily Turfan.
Having triumphed over the An Lushan rebellion, while the Tang emperor had been forced to flee in humiliation, the Uighurs were now the heroes of the day. The Tang government had not only lost face, but was in an even weaker position than before to exercise effective control over Turfan or anywhere else in the Tarim Basin. Although Tang China had given the Sogdians political asylum in 713, yet by expelling the Buddhist monks among them, they had undoubtedly lost the confidence of the Sogdian community. If the Uighurs were to adopt a major Sogdian religion, they would readily be accepted as the protectors and overlords of the Turfan Sogdians. This would give them a foothold in the Tarim Basin for further expansion and possible control of the Silk Route.
The Conversion to Manichaeism
It was undoubtedly with such thoughts in mind that Bogu Qaghan declared Manichaeism the Uighur state religion in 762, since Buddhism was not a viable alternative at this time. Furthermore, with its stress on the forces of light gaining the victory over the powers of darkness, Manichaeism would have given the impression of being more suited than Buddhism for a martial nation. Following the lessons learned from the First and Second Eastern Turk Dynasties, the Qaghan borrowed the Sogdian alphabet, but not the Sogdian language, and modified it for writing Uighur. He used it for both administrative as well as religious purposes, employing Sogdians to translate Manichaean texts into Uighur.
Having gained experience translating Buddhist texts into Old Turk, the Sogdians had begun to render Buddhist scriptures into their own language during the interim (630 – 682) between the First and Second Eastern Turk Dynasties. This was the period when not only Mongolia and Turfan, but also the entire Tarim Basin had been conquered by Tang China. The Sogdian translators had used primarily Han Chinese sources, the tradition and language with which they were most familiar. With Tang China in such a dominant political position, the Sogdian Buddhists probably had finally felt their identity threatened enough to take this step to distance themselves from possible absorption by Han Chinese culture. Since this Buddhist translation activity was still continuing at the time the Uighurs commissioned the Sogdian translators to prepare Uighur Manichaean texts, and since the Sogdians had already worked with the Old Turk language which was related to Uighur, the Sogdians naturally borrowed a considerable amount of Buddhist terminology for their new task.
Popular Resistance to the Conversion
As a result of the Uighur rule of Turfan from 605 to the 630s, many Uighurs had already adopted the Eastern Turk form of Buddhism, particularly the warriors and common people. Yet after the Uighur suppression of the An Lushan rebellion, Bogu Qaghan led his men in destroying all Buddhist monasteries and temples when pillaging Chang’an and Loyang. He ordered the subsequent destruction of Buddhist monasteries in other parts of his realm as well, as far away as Semirechye in northern West Turkistan. In so doing, he was undoubtedly trying to reaffirm the pan-Turkic martial tradition and justify his choice of Manichaeism by demonstrating even further the weakness of Buddhism.
Numerous Uighur soldiers, however, undoubtedly still followed a mixture of Buddhism, Tengrism, and Turkic shamanism at this time. This is indicated by the fact that Bogu Qaghan had to force his people into accepting Manichaeism. He organized them into units of ten, with one person responsible for the religious observances of each group. Nevertheless, this mainly Sogdian religion never became widespread among the Uighurs. It was limited primarily to the aristocratic nobility, to whom it appealed because of its emphasis on a pure and clean religious elite who were morally superior to the so-called “dirty masses.” Buddhism undoubtedly continued among these “dirty masses” throughout the period of Uighur rule over Mongolia.
Furthermore, the Uighur nobility itself was not exclusively committed to Manichaeism. Twenty years after the official state conversion, Alp Qutlugh (r. 780 – 790) assassinated Bogu Qaghan for his financial excesses in support of this new religion. Assuming the title qaghan, he requested Patriarch Timotheus (r. 780 – 819) to assign a Nestorian Christian metropolitan for his realm. This form of Christianity, however, like Manichaeism, was still basically a Sogdian faith. Its patronage fit logically within the general Uighur strategy for winning the allegiance of the people of the Tarim Basin as led economically by the Sogdian merchants.
Summary of the Central Asian Pattern of Religious Conversion
These examples of the Eastern Turk and Uighur conversions are illustrative, then, of the phenomenon of Central Asian Turkic nations changing religions. When such changes were made by rulers on a voluntary basis, they were mostly part of a calculated political strategy to gain power and support or economic advantage, rather than a spiritual decision.
One must not be too cynical in assigning purely Machiavellian motives to these conversions, however, and totally dismiss any religious considerations. There must be elements in the religion to be adopted that resonate with the mentality of the local culture; otherwise, no one would be able to relate to the faith. Nevertheless, one must also not be idealistic and imagine that Central Asian rulers of people with strong martial traditions made their decisions about such matters based purely on their appreciation of the superiority of the sophisticated metaphysical intricacies of one religion over another. They were more impressed when a religion provided the supernatural power that led to military victory, and changed national religion seeking similar support for their own expansionist efforts.
This was true not only in these instances with the Eastern Turks and Uighurs, but was also the case with the Tibetan Emperor Songtsen-gampo’s interest in Buddhism in the mid-seventh century. It also explains why the Tibetan court around the young Emperor Mey-agtsom was open to considering Islam in the early ninth century, when it might help them gain more territory through their alliance with the Abbasids and why, when such advantage was not forthcoming, they lost total interest in the Muslim faith.