During the Lama Rebellion of 1932, priests led thousands of people and 7 million head of livestock into Inner Mongolia.
Proclaimed an independent state (from China) in July 1921, Mongolia (called Mengguguo by the Chinese today), remained a monarchy until the Living Buddha (Jebtsun Damba Khutukhtu) died in 1924. With the establishment of the Mongolian People's Republic (MPR) in November, 1924, it became the second communist country in history.
This was followed by a struggle to divest the old privileged classes of their capital (largely land and livestock) and the persecution of the Lama priests. This led to the Lama Rebellion of 1932 when priests led thousands of people, along with about 7 million head of livestock, across the border into Inner Mongolia. A new constitution, adopted in 1940, consolidated the power of the Communist regime.