Not until the Mongols had answered Chu's rising with a tightening of the nationality laws did the revolutionary movement become a national movement, directed against the foreigners as such. And only when Chu came under the influence of the first people of the gentry who joined him, whether voluntarily or perforce, did what had been a revolutionary movement become a struggle for the substitution of one dynasty for another without interfering with the existing social system. Both these points were of the utmost importance to the whole development of the Ming epoch. The Mongols were driven out fairly quickly and without great difficulty. The Chinese drew from the ease of their success a sense of superiority and a clear feeling of nationalism. This feeling should not be confounded with the very old feeling of Chinese as a culturally superior group according to which, at least in theory though rarely in practice, every person who assimilated Chinese cultural values and traits was a "Chinese". The roots of nationalism seem to lie in the Southern Sung period, growing up in the course of contacts with the Juchên and Mongols; but the discriminatory laws of the Mongols greatly fostered this feeling. From now on, it was regarded a shame to serve a foreigner as official, even if he was a ruler of China. 2 _Wars against Mongols and Japanese_ It had been easy to drive the Mongols out of China, but they were never really beaten in their own country. On the contrary, they seem to have regained strength after their withdrawal from China: they reorganized themselves and were soon capable of counter-thrusts, while Chinese offensives had as a rule very little success, and at all events no decisive success. In the course of time, however, the Chinese gained a certain influence over Turkestan, but it was never absolute, always challenged. After the Mongol empire had fallen to pieces, small states came into existence in Turkestan, for a long time with varying fortunes; the most important one during the Ming epoch was that of Hami, until in 1473 it was occupied by the city-state of Turfan. At this time China actively intervened in the policy of Turkestan in a number of combats with the Mongols. As the situation changed from time to time, these city-states united more or less closely with China or fell away from her altogether. In this period, however, Turkestan was of no military or economic importance to China.