According to Wikipedia, the territory now called Mongolia was conquered by White Russians in 1920. Before then it was controlled by the Chinese Republic and bef

According to Wikipedia, the territory now called Mongolia was conquered by White Russians in 1920. Before then it was controlled by the Chinese Republic and before that the Qing dynasty (the rulers of which were ethnically neither Chinese nor Mongolian). In response, the Red Russians assisted Mongolian communists in conquering the country. The assistance included the sending of Russian troops.