Mongolian Revolution of 1921: The Mongolian People's Army defeats local Chinese forces at Altanbulag, Selenge (then known as Maimachen). This battle was seen as the birthday of the People's Army and completed the expulsion of Chinese militants in Mongolia.

The Mongolian Revolution of 1921, locally known as the People's Revolution of 1921, was a military and political event by which Mongolian revolutionaries, with the assistance of the Soviet Red Army, expelled Russian White Guards from the country, and founded the Mongolian People's Republic in 1924.…