As the Tibetans were the predominant power in the Tarim basin from at least the middle of the eighth until the middle of the ninth century, it is not surprising that great stores of Tibetan manuscripts have been found in the regions of Khotan, Miran and Tun-huang. In Turfan, as lying more to the north, traces of Tibetan influence, though not absent, are fewer. The documents discovered must be anterior to the ninth century and comprise numerous official and business papers as well as Buddhist translations[468]. They are of great importance for the history of the Tibetan language and also indicate that at the period when they were written Buddhism at most shared with the Bön religion the allegiance of the Tibetans. No Manichæan or Christian translations in Tibetan have yet been discovered.
Vast numbers of Chinese texts both religious and secular are preserved in all the principal centres and offer many points of interest among which two may be noticed. Firstly the posts on the old military frontier near Tun-huang have furnished a series of dated documents ranging from 98 B.C. to 153 A.D.[469] There is therefore no difficulty in admitting that there was intercourse between China and Central Asia at this period. Secondly, some documents of the T'ang dynasty are Manichæan, with an admixture of Buddhist and Taoist ideas[470].
The religious monuments of Central Asia comprise stupas, caves and covered buildings used as temples or vihâras. Buddhist, Manichæan and Christian edifices have been discovered but apparently no shrines of the Zoroastrian religion, though it had many adherents in these regions, and though representations of Hindu deities have been found, Hinduism is not known to have existed apart from Buddhism[471]. Caves decorated for Buddhist worship are found not only in the Tarim basin but at Tun-huang on the frontier of China proper, near Ta-t'ung-fu in northern Shensi, and in the defile of Lung-mên in the province of Ho-nan. The general scheme and style of these caves are similar, but while in the last two, as in most Indian caves, the figures and ornaments are true sculpture, in the caves of Tun-huang and the Tarim not only is the wall prepared for frescoes, but even the figures are executed in stucco. This form of decoration was congenial to Central Asia for the images which embellished the temple walls were moulded in the same fashion. Temples and caves were sometimes combined, for instance at Bäzäklik where many edifices were erected on a terrace in front of a series of caves excavated in a mountain corner. Few roofed buildings are well preserved but it seems certain that some were high quadrilateral structures, crowned by a dome of a shape found in Persia, and that others had barrel-shaped roofs, apparently resembling the chaityas of Ter and Chezarla[472]. Le Coq states that this type of architecture is also found in Persia[473]. The commonest type of temple was a hall having at its further end a cella, with a passage behind to allow of circumambulation. Such halls were frequently enlarged by the addition of side rooms and sometimes a shrine was enclosed by several rectangular courts[474].