Nikolai Robert Maximilian Freiherr von Ungern-Sternberg (Russian: -, romanized: Roman Fedorovich fon Ungern-Shternberg; 10 January 1886 15 September 1921), often referred to as Roman von Ungern-Sternberg or Baron Ungern, was an anticommunist general in the Russian Civil War and then an independent warlord who intervened in Mongolia against China. A part of the Russian Empire's Baltic German minority, Ungern was an ultraconservative monarchist who aspired to restore the Russian monarchy after the 1917 Russian Revolutions and to revive the Mongol Empire under the rule of the Bogd Khan. His attraction to Vajrayana Buddhism and his eccentric, often violent, treatment of enemies and his own men earned him the sobriquet "the Mad Baron" or "the Bloody Baron".

In February 1921, at the head of the Asiatic Cavalry Division, Ungern expelled Chinese troops from Mongolia and restored the monarchic power of the Bogd Khan. During his five-month occupation of Outer Mongolia, Ungern imposed order on the capital city, Ikh Khree (now Ulaanbaatar), by fear, intimidation and brutal violence against his opponents, particularly the Bolsheviks. In June 1921, he travelled to eastern Siberia to support anti-Bolshevik partisan forces and to head off a joint Red Army-Mongolian rebel invasion. That action ultimately led to his defeat and capture two months later. He was taken prisoner by the Red Army and, a month later, was put on trial for "counter-revolution" in Novonikolaevsk. After a six-hour show trial, he was found guilty and on 15 September 1921 he was executed.

Mongolia ( (listen), Mongolian: Монгол Улс, romanized: Mongol Uls, Traditional Mongolian: Moŋğol ulus; lit. "Mongol Nation" or "State of Mongolia") is a landlocked country in East Asia, bordered by Russia to the north and China to the south. It covers an area of 1,564,116 square kilometres (603,909 square miles), with a population of just 3.3 million, making it the world's most sparsely populated sovereign nation. Mongolia is the world's largest landlocked country that does not border a closed sea, and much of its area is covered by grassy steppe, with mountains to the north and west and the Gobi Desert to the south. Ulaanbaatar, the capital and largest city, is home to roughly half of the country's population.

The territory of modern-day Mongolia has been ruled by various nomadic empires, including the Xiongnu, the Xianbei, the Rouran, the First Turkic Khaganate, and others. In 1206, Genghis Khan founded the Mongol Empire, which became the largest contiguous land empire in history. His grandson Kublai Khan conquered China to establish the Yuan dynasty. After the collapse of the Yuan, the Mongols retreated to Mongolia and resumed their earlier pattern of factional conflict, except during the era of Dayan Khan and Tumen Zasagt Khan. In the 16th century, Tibetan Buddhism spread to Mongolia, being further led by the Manchu-founded Qing dynasty, which absorbed the country in the 17th century. By the early 20th century, almost one-third of the adult male population were Buddhist monks. After the collapse of the Qing dynasty in 1911, Mongolia declared independence, and achieved actual independence from the Republic of China in 1921. Shortly thereafter, the country became a satellite state of the Soviet Union, which had aided its independence from China. In 1924, the Mongolian People's Republic was founded as a socialist state. After the anti-communist revolutions of 1989, Mongolia conducted its own peaceful democratic revolution in early 1990. This led to a multi-party system, a new constitution of 1992, and transition to a market economy.

Approximately 30% of the population is nomadic or semi-nomadic; horse culture remains integral. Buddhism is the majority religion, with the nonreligious being the second-largest group. Islam is the second-largest religion, concentrated among ethnic Kazakhs. Most citizens are ethnic Mongols, with roughly 5% of the population being Kazakhs, Tuvans, and other minorities, who are especially concentrated in the west. Mongolia is a member of the United Nations, Asia Cooperation Dialogue, G77, Asian Infrastructure Investment Bank, Non-Aligned Movement and a NATO global partner. Mongolia joined the World Trade Organization in 1997 and seeks to expand its participation in regional economic and trade groups.