In 1203 AD, a single Mongolian state was formed based on nomadic tribal groupings under the leadership of Genghis Khan. He and his immediate successors conquered nearly all of Asia and European Russia and sent armies as far as Central Europe and Southeast Asia. Genghis Khan's grandson Kublai Khan, who conquered China and established the Yuan dynasty (1279-1368 AD), gained fame in Europe through the writings of Marco Polo.
Although Mongol-led confederations sometimes exercised wide political power over their conquered territories, their strength declined rapidly after the Mongol dynasty in China was overthrown in 1368.
The Manchus, a tribal group which conquered China in 1644 and formed the Qing dynasty, were able to bring Mongolia under Manchu control in 1691 as Outer Mongolia when the Khalkha Mongol nobles swore an oath of allegiance to the Manchu emperor. The Mongol rulers of Outer Mongolia enjoyed considerable autonomy under the Manchus, and all Chinese claims to Outer Mongolia following the establishment of the republic have rested on this oath. In 1727, Russia and Manchu China concluded the Treaty of Khiakta, delimiting the border between China and Mongolia that exists in large part today.
Outer Mongolia was a Chinese province (1691-1911), an autonomous state under Russian protection (1912-19), and again a Chinese province (1919- 21). As Manchu authority in China waned, and as Russia and Japan confronted each other, Russia gave arms and diplomatic support to nationalists among the Mongol religious leaders and nobles. The Mongols accepted Russian aid and proclaimed their independence of Chinese rule in 1911, shortly after a successful Chinese revolt against the Manchus. By agreements signed in 1913 and 1915, the Russian Government forced the new Chinese Republican Government to accept Mongolian autonomy under continued Chinese control, presumably to discourage other foreign powers from approaching a newly independent Mongolian state that might seek support from as many foreign sources as possible.
The Russian revolution and civil war afforded Chinese warlords an opportunity to re-establish their rule in Outer Mongolia, and Chinese troops were dispatched there in 1919. Following Soviet military victories over White Russian forces in the early 1920s and the occupation of the Mongolian capital Urga in July 1921, Moscow again became the major outside influence on Mongolia. The Mongolian People's Republic was proclaimed on November 25, 1924.
Between 1925 and 1928, power under the communist regime was consolidated by the Mongolian Peoples Revolutionary Party (MPRP). The MPRP left gradually undermined rightist elements, seizing control of the party and the government. Several factors characterized the country during this period--the society was basically nomadic and illiterate; there was no industrial proletariat; the aristocracy and the religious establishment shared the country's wealth; there was widespread popular obedience to traditional authorities; the party lacked grassroots support; and the government had little organization or experience.
In an effort at swift socioeconomic reform, the leftist government applied extreme measures which attacked the two most dominant institutions in the country--the aristocracy and the religious establishment. Between 1932 and 1945, their excess zeal, intolerance, and inexperience led to anti-communist uprisings. In the late 1930's purges directed at the religious institution resulted in the desecration of hundreds of Buddhist institutions and imprisonment of more than 10,000 people.
During World War II, because of a growing Japanese threat over the Mongolian-Manchurian border, the Soviet Union reversed the course of Mongolian socialism in favor of a new policy of economic gradualism and buildup of the national defense. The Soviet-Mongolian army defeated Japanese forces that had invaded eastern Mongolia in the summer of 1939, and a truce was signed setting up a commission to define the Mongolian-Manchurian border in the autumn of that year.
Following the war, the Soviet Union reasserted its influence in Mongolia. Secure in its relations with Moscow, the Mongolian Government shifted to postwar development, focusing on civilian enterprise. International ties were expanded, and Mongolia established relations with North Korea and the new communist governments in Eastern Europe. It also increased its participation in communist-sponsored conferences and international organizations. Mongolia became a member of the United Nations in 1961.
In the early 1960s, Mongolia attempted to maintain a neutral position amidst increasingly contentious Sino-Soviet polemics; this orientation changed in the middle of the decade. Mongolia and the Soviet Union signed an agreement in 1966 that introduced large-scale Soviet ground forces as part of Moscow's general buildup along the Sino-Soviet frontier.
During the period of Sino-Soviet tensions, relations between Mongolia and China deteriorated. In 1983, Mongolia systematically began expelling some of the 7,000 ethnic Chinese in Mongolia to China. Many of them had lived in Mongolia since the 1950s, when they were sent there to assist in construction projects.