Bulgaria's Tsar Boris III died unexpectedly in 1943

Tsar Boris III of Bulgaria died unexpectedly on August 28, 1943, at the age of 49 in his palace in Sofia. His death occurred shortly after a visit to Adolf Hitler in Germany, sparking long-standing historical debates regarding the cause of his passing.

Official medical reports attributed his death to heart and lung complications following a brief illness. However, various hypotheses suggest potential poisoning. Some theories point to German involvement, noting that Hitler was reportedly angered by the Tsar’s refusal to send troops to the Eastern Front or to hand over Bulgarian Jews. Historical accounts mention suspicions of a slow-acting poison, similar to one found in the autopsy of Greek Prime Minister Ioannis Metaxas.

Boris III ruled Bulgaria from 1918 through the challenges of the Second World War, including the country's alignment with the Tripartite Pact in 1941. Following his death, his six-year-old son, Simeon Ternevski, was proclaimed Tsar Simeon II, with a regency established to manage the throne during his minority.