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.