The first two generals had considerable success, but Ko-shu Han, whose task was to prevent access to the western capital, was quickly defeated and taken prisoner. The emperor fled betimes, and An Lu-shan captured Ch'ang-an. The emperor now abdicated; his son, emperor Su Tsung (756-762), also fled, though not with him into Szechwan, but into north-western Shensi. There he defended himself against An Lu-shan and his capable general Shih Ssŭ-ming (himself a Turk), and sought aid in Central Asia. A small Arab troop came from the caliph Abu-Jafar, and also small bands from Turkestan; of more importance was the arrival of Uighur cavalry in substantial strength. At the end of 757 there was a great battle in the neighbourhood of the capital, in which An Lu-shan was defeated by the Uighurs; shortly afterwards he was murdered by one of his eunuchs. His followers fled; Loyang was captured and looted by the Uighurs. The victors further received in payment from the T'ang government 10,000 rolls of silk with a promise of 20,000 rolls a year; the Uighur khan was given a daughter of the emperor as his wife. An Lu-shan's general, the Turk Shih Ssŭ-ming, entered into An Lu-shan's heritage, and dominated so large a part of eastern China that the Chinese once more made use of the Uighurs to bring him down. The commanders in the fighting against Shih Ssŭ-ming this time were once more Kuo Tzŭ-i and the Kitan general, together with P'u-ku Huai-en, a member of a Tölös family that had long been living in China. At first Shih Ssŭ-ming was victorious, and he won back Loyang, but then he was murdered by his own son, and only by taking advantage of the disturbances that now arose were the government troops able to quell the dangerous rising. In all this, two things seem interesting and important. To begin with, An Lu-shan had been a military governor. His rising showed that while this new office, with its great command of power, was of value in attacking external enemies, it became dangerous, especially if the central power was weak, the moment there were no external enemies of any importance. An Lu-shan's rising was the first of many similar ones in the later T'ang period. The gentry of eastern China had shown themselves entirely ready to support An Lu-shan against the government, because they had hoped to gain advantage as in the past from a realm with its centre once more in the east. In the second place, the important part played by aliens in events within China calls for notice: not only were the rebels An Lu-shan and Shih Ssŭ-ming non-Chinese, but so also were most of the generals opposed to them. But they regarded themselves as Chinese, not as members of another national group. The Turkish Uighurs brought in to help against them were fighting actually against Turks, though they regarded those Turks as Chinese. We must not bring to the circumstances of those times the present-day notions with regard to national feeling.