History of Mongolia: Short Version
1933, the Russian Empire was at a height, Mongolia only was in Mongolia, and China to the south was undergoing a revoultion. When the Russian Empire split in 1935, forming the Siberian Union, and Russia, Mongolia took up as one of the remaining Warsaw Pact members, a leader of the local area. In 1936, Mongolia declared war on China, and the rebels, taking much of Manchuria and Western China, before the seige of Peking began. When Peking was captured, most of the Chinese army was destroyed, and the Mongols poured into Central China. The rebels saw that they couldn't win, and signed over there land to Mongolia. The Chinese remants in the south collapsed, and they were one of the strongest powerin Asia.
Korea, undergoing a revoultion of its own, when Mongolia entered on North Korea's side, helped defeat the South. In 1946, The Korean's joined the People's Republic of Mongolia and been in since. The Mongols and Tibetan people fight over land in Western and Central China many times, usaually ending in a stalemate.