The Qing Dynasty (1644-1911) was founded after the Manchus defeated the Ming, the last Han Chinese dynasty. The Manchus introduced a 'queue order', forcing the Han Chinese to adopt the Manchu queue hairstyle and Manchu-style clothing. The Qing consolidated control of some areas originally under the Ming, including Yunnan. They also stretched their sphere of influence over Xinjiang, Tibet and Mongolia. But during the 19th century, Qing control weakened. Britain's desire to continue its opium trade with China collided with imperial edicts prohibiting the addictive drug, and the First Opium War erupted in 1840. Hong Kong was ceded to Britain in 1842 under the Treaty of Nanking. At the start of the 20th century, the Boxer Rebellion threatened northern China. This was a conservative anti-imperialist movement that sought to return China to old ways. The Empress Dowager, probably seeking to ensure her continued grip on power, sided with the Boxers when they advanced on Beijing. But an Eight-N