What could take their place? The alien rulers had left little behind them. Most of them had been unable to write Chinese, and in so far as they were warriors they had no interest in literature or in political philosophy, for they were men of action. Few songs and poems of theirs remain extant in translations from their language into Chinese, but these preserve a strong alien flavour in their mental attitude and in their diction. They are the songs of fighting men, songs that were sung on horseback, songs of war and its sufferings. These songs have nothing of the excessive formalism and aestheticism of the Chinese, but give expression to simple emotions in unpolished language with a direct appeal. The epic of the Turkish peoples had clearly been developed already, and in north China it produced a rudimentary ballad literature, to which four hundred years later no less attention was paid than to the emotional world of contemporary songs.

The actual literature, however, and the philosophy of this period are Buddhist. How can we explain that Buddhism had gained such influence?

It will be remembered that Buddhism came to China overland and by sea in the Han epoch. The missionary monks who came from abroad with the foreign merchants found little approval among the Chinese gentry. They were regarded as second-rate persons belonging, according to Chinese notions, to an inferior social class. Thus the monks had to turn to the middle and lower classes in China. Among these they found widespread acceptance, not of their profound philosophic ideas, but of their doctrine of the after life. This doctrine was in a certain sense revolutionary: it declared that all the high officials and superiors who treated the people so unjustly and who so exploited them, would in their next reincarnation be born in poor circumstances or into inferior rank and would have to suffer punishment for all their ill deeds. The poor who had to suffer undeserved evils would be born in their next life into high rank and would have a good time. This doctrine brought a ray of light, a promise, to the country people who had suffered so much since the later Han period of the second century A.D. Their situation remained unaltered down to the fourth century; and under their alien rulers the Chinese country population became Buddhist.

The merchants made use of the Buddhist monasteries as banks and warehouses. Thus they, too, were well inclined towards Buddhism and gave money and land for its temples. The temples were able to settle peasants on this land as their tenants. In those times a temple was a more reliable landlord than an individual alien, and the poorer peasants readily became temple tenants; this increased their inclination towards Buddhism.

The Indian, Sogdian, and Turkestani monks were readily allowed to settle by the alien rulers of China, who had no national prejudice against other aliens. The monks were educated men and brought some useful knowledge from abroad. Educated Chinese were scarcely to be found, for the gentry retired to their estates, which they protected as well as they could from their alien ruler. So long as the gentry had no prospect of regaining control of the threads of political life that extended throughout China, they were not prepared to provide a class of officials and scholars for the anti-Confucian foreigners, who showed interest only in fighting and trading. Thus educated persons were needed at the courts of the alien rulers, and Buddhists were therefore engaged. These foreign Buddhists had all the important Buddhist writings translated into Chinese, and so made use of their influence at court for religious propaganda.

This does not mean that every text was translated from Indian languages; especially in the later period many works appeared which came not from India but from Sogdia or Turkestan, or had even been written in China by Sogdians or other natives of Turkestan, and were then translated into Chinese. In Turkestan, Khotan in particular became a centre of Buddhist culture. Buddhism was influenced by vestiges of indigenous cults, so that Khotan developed a special religious atmosphere of its own; deities were honoured there (for instance, the king of Heaven of the northerners) to whom little regard was paid elsewhere. This "Khotan Buddhism" had special influence on the Buddhist Turkish peoples.

Big translation bureaux were set up for the preparation of these translations into Chinese, in which many copyists simultaneously took down from dictation a translation made by a "master" with the aid of a few native helpers. The translations were not literal but were paraphrases, most of them greatly reduced in length, glosses were introduced when the translator thought fit for political or doctrinal reasons, or when he thought that in this way he could better adapt the texts to Chinese feeling.

Buddhism, quite apart from the special case of "Khotan Buddhism", underwent extensive modification on its way across Central Asia. Its main Indian form (Hinayana) was a purely individualistic religion of salvation without a God—related in this respect to genuine Taoism—and based on a concept of two classes of people: the monks who could achieve salvation and, secondly, the masses who fed the monks but could not achieve salvation. This religion did not gain a footing in China; only traces of it can be found in some Buddhistic sects in China. Mahayana Buddhism, on the other hand, developed into a true popular religion of salvation. It did not interfere with the indigenous deities and did not discountenance life in human society; it did not recommend Nirvana at once, but placed before it a here-after with all the joys worth striving for. In this form Buddhism was certain of success in Asia. On its way from India to China it divided into countless separate streams, each characterized by a particular book. Every nuance, from profound philosophical treatises to the most superficial little tracts written for the simplest of souls, and even a good deal of Turkestan shamanism and Tibetan belief in magic, found their way into Buddhist writings, so that some Buddhist monks practised Central Asian Shamanism.