The success of the Qing dynasty in maintaining the old order proved a liability when the empire was confronted with growing challenges from seafaring Western powers. The centuries of peace and self-satisfaction dating back to Ming times had encouraged little change in the attitudes of the ruling elite. The imperial Neo-Confucian scholars accepted as axiomatic the cultural superiority of Chinese civilization and the position of the empire at the hub of their perceived world. To question this assumption, to suggest innovation, or to promote the adoption of foreign ideas was viewed as tantamount to heresy. Imperial purges dealt severely with those who deviated from orthodoxy.
By the nineteenth century, China was experiencing growing internal pressures of economic origin. By the start of the century, there were over 300 million Chinese, but there was no industry or trade of sufficient scope to absorb the surplus labor. Moreover, the scarcity of land led to widespread rural discontent and a breakdown in law and order. The weakening through corruption of the bureaucratic and military systems and mounting urban pauperism also contributed to these disturbances. Localized revolts erupted in various parts of the empire in the early nineteenth century. Secret societies, such as the White Lotus sect () in the north and the Triad Society () in the south, gained ground, combining anti-Manchu subversion with banditry.

The Western Powers Arrive
As elsewhere in Asia, in China the Portuguese were the pioneers, establishing a foothold at Macao ( or Aomen in pinyin), from which they monopolized foreign trade at the Chinese port of Guangzhou ( or Canton). Soon the Spanish arrived, followed by the British and the French.
Trade between China and the West was carried on in the guise of tribute: foreigners were obliged to follow the elaborate, centuries-old ritual imposed on envoys from China's tributary states. There was no conception at the imperial court that the Europeans would expect or deserve to be treated as cultural or political equals. The sole exception was Russia, the most powerful inland neighbor.
The Manchus were sensitive to the need for security along the northern land frontier and therefore were prepared to be realistic in dealing with Russia. The Treaty of Nerchinsk (1689) with the Russians, drafted to bring to an end a series of border incidents and to establish a border between Siberia and Manchuria (northeast China) along the Heilong Jiang ( or Amur River), was China's first bilateral agreement with a European power. In 1727 the Treaty of Kiakhta delimited the remainder of the eastern portion of the Sino-Russian border. Western diplomatic efforts to expand trade on equal terms were rebuffed, the official Chinese assumption being that the empire was not in need of foreign--and thus inferior--products. Despite this attitude, trade flourished, even though after 1760 all foreign trade was confined to Guangzhou, where the foreign traders had to limit their dealings to a dozen officially licensed Chinese merchant firms.
Trade was not the sole basis of contact with the West. Since the thirteenth century, Roman Catholic missionaries had been attempting to establish their church in China. Although by 1800 only a few hundred thousand Chinese had been converted, the missionaries--mostly Jesuits--contributed greatly to Chinese knowledge in such fields as cannon casting, calendar making, geography, mathematics, cartography, music, art, and architecture. The Jesuits were especially adept at fitting Christianity into a Chinese framework and were condemned by a papal decision in 1704 for having tolerated the continuance of Confucian ancestor rites among Christian converts. The papal decision quickly weakened the Christian movement, which it proscribed as heterodox and disloyal.
The Opium War, 1839-42
During the eighteenth century, the market in Europe and America for tea, a new drink in the West, expanded greatly. Additionally, there was a continuing demand for Chinese silk and porcelain. But China, still in its preindustrial stage, wanted little that the West had to offer, causing the Westerners, mostly British, to incur an unfavorable balance of trade. To remedy the situation, the foreigners developed a third-party trade, exchanging their merchandise in India and Southeast Asia for raw materials and semiprocessed goods, which found a ready market in Guangzhou. By the early nineteenth century, raw cotton and opium () from India had become the staple British imports into China, in spite of the fact that opium was prohibited entry by imperial decree. The opium traffic was made possible through the connivance of profit-seeking merchants and a corrupt bureaucracy.
In 1839 the Qing government, after a decade of unsuccessful anti-opium campaigns, adopted drastic prohibitory laws against the opium trade. The emperor dispatched a commissioner, Lin Zexu ( 1785-1850), to Guangzhou to suppress illicit opium traffic. Lin seized illegal stocks of opium owned by Chinese dealers and then detained the entire foreign community and confiscated and destroyed some 20,000 chests of illicit British opium. The British retaliated with a punitive expedition, thus initiating the first Anglo-Chinese war, better known as the Opium War (1839-42). Unprepared for war and grossly underestimating the capabilities of the enemy, the Chinese were disastrously defeated, and their image of their own imperial power was tarnished beyond repair. The Treaty of Nanjing (1842), signed on board a British warship by two Manchu imperial commissioners and the British plenipotentiary, was the first of a series of agreements with the Western trading nations later called by the Chinese the "unequal treaties." Under the Treaty of Nanjing, China ceded the island of Hong Kong ( or Xianggang in pinyin) to the British; abolished the licensed monopoly system of trade; opened 5 ports to British residence and foreign trade; limited the tariff on trade to 5 percent ad valorem; granted British nationals extraterritoriality (exemption from Chinese laws); and paid a large indemnity. In addition, Britain was to have most-favored-nation treatment, that is, it would receive whatever trading concessions the Chinese granted other powers then or later. The Treaty of Nanjing set the scope and character of an unequal relationship for the ensuing century of what the Chinese would call "national humiliations." The treaty was followed by other incursions, wars, and treaties that granted new concessions and added new privileges for the foreigners.