During the early 19th century, the Qing Dynasty declined rapidly. Britain smuggled into China large quantities of opium, and in response the Qing government imposed a ban on the drug. In an effort to protect its opium trade, Britain launched a war against China in 1840, which led to the Qing government's signing with the British government the Treaty of Nanking, 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 200-odd-year-old Qing Dynasty, ending over 2,000 years of feudal monarchy, and established the Republic of China.
