During the 19th century, the Qing Dynasty declined rapidly. Britain smuggled large quantities of opium into China, making the Qing government impose a ban on the drug. In an effort to protect its opium trade, Britain launched a war of aggression against China in 1840. The Qing government finally signed the Treaty of Nanking, a treaty of national betrayal and humiliation, with the British government. Many countries, including Britain, the United States, France, Russia and Japan, forced the Qing government to sign various unequal treaties following the Opium War. China was gradually relegated to a semi-colonial, semi-feudal country.
The Revolution of 1911 led by Dr. Sun Yat-sen was one of the greatest events in modern Chinese history, as it overthrew the 200-odd-year-old Qing Dynasty, ending over 2,000 years of feudal monarchy, and established the Republic of China.