sent resident commissioners called Ambans to Lhasa. In 1750, the Ambans and the majority of the Han Chinese and Manchus living in Lhasa were killed in a riot, and Qing troops arrived quickly and suppressed the rebels in the next year. Like the preceding Yuan dynasty, the Manchus of the Qing dynasty exerted military and administrative control of the region, while granting it a degree of political autonomy. The Qing commander publicly executed a number of supporters of the rebels and, as in 1723 and 1728, made changes in the political structure and drew up a formal organization plan. The Qing now restored the Dalai Lama as ruler, leading the governing council called Kashag, but elevated the role of Ambans to include more direct involvement in Tibetan internal affairs. At the same time, the Qing took steps to counterbalance the power of the aristocracy by adding officials recruited from the clergy to key posts. For several decades, peace reigned in Tibet, but in 1792, the Qing Qianlong Emperor sent a large Chinese army into Tibet to push the invading Nepalese out. This prompted yet another Qing reorganization of the Tibetan government, this time through a written plan called the "Twenty-Nine Regulations for Better Government in Tibet". Qing military garrisons staffed with Qing troops were now also established near the Nepalese border. Tibet was dominated by the Manchus in various stages in the 18th century, and the years immediately following the 1792 regulations were the peak of the Qing imperial commissioners' authority; but there was no attempt to make Tibet a Chinese province. In 1834, the Sikh Empire invaded and annexed Ladakh, a culturally Tibetan region that was an independent kingdom at the time. Seven years later, a Sikh army led by General Zorawar Singh invaded western Tibet from Ladakh, starting the Sino-Sikh War. A Qing-Tibetan army repelled the invaders but was in turn defeated when it chased the Sikhs into Ladakh. The war ended with the signing of the Treaty of Chushul between the Chinese and Sikh empires. As the Qing dynasty weakened, its authority over Tibet also gradually declined, and by the mid-19th century, its influence was minuscule. Qing authority over Tibet had become more symbolic than real by the late 19th century, although in the 1860s, the Tibetans still chose for reasons of their own to emphasize the empire's symbolic authority and make it seem substantial. In 1774,