Boris III of Bulgaria

Boris III became Tsar in 1918 when his father abdicated following Bulgaria's loss in World War I. The Treaty of Neuilly stripped Bulgaria of territory and imposed crippling reparations. Through the 1920s he recognized governments that came and went by coup and suppression, including Aleksandar Tsankov's harsh crackdown on communists. In 1935 Boris overthrew the Zveno movement and ruled as a de facto absolute monarch for the rest of his life. He kept Bulgaria neutral into 1940, then installed Nazi sympathizer Bogdan Filov as prime minister, signed the anti-Semitic Law for Protection of the Nation in January 1941, and joined the Axis two months later. Bulgaria received chunks of Yugoslavia and Greece but stayed out of the invasion of the Soviet Union. Authorities deported most Jews from occupied territories to Treblinka; under public pressure Boris halted the deportation of Bulgarian Jews while expelling nearly 20,000 to forced labor camps in the countryside. In August 1943, shortly after returning from Germany, he died. His six-year-old son Simeon II succeeded him.