Roman von Ungern-Sternberg, Austrian-Russian general (d. 1921)
Nikolai Robert Maximilian Freiherr von Ungern-Sternberg (Russian: Роман Фёдорович фон Унгерн-Штернберг, 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 Khüree (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.