During the early 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, which led to the Qing government's signing with the British government the Treaty of Nanjing, a treaty of national betrayal and humiliation. 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 Qing Dynasty that had ruled for some 270 years, ended over 2,000 years of feudal monarchy, and established the Republic of China.