On 15 September 1946, Bulgaria was declared a People's Republic in accordance with the referendum of 8 September. It was headed by Prime Minister Georgi Dimitrov.
Two days after the Soviet invasion of Bulgaria in 1944, a communist military coup occurred in Sofia. Power was gained by the communist Provisional Government headed by Vasil Kolarov. The referendum was held on 8 September 1946, after which the Bulgarians renounced their monarchy. Supporters of the monarchy claimed that the results had been rigged and influenced by the Red Army.
After the state transitioned from monarchy to republic, the armed underground resistance, consisting of those who disagreed with communist policy, started to operate all over the country. Initially, these groups consisted mainly of former police officers and soldiers, but after collectivisation was introduced, they gained popular support, especially among the peasantry. The Goryani movement, or Goryantsvo, was founded by opponents of the regime, who defied the authorities from 1947 to 1956. The Goryantsvo’s activists fought the communist system, collectivisation and nationalisation, political repression, and the “Sovietisation” of Bulgaria, advocating instead a return to freedom, democracy and the market economy. By the late Fifties, their activities had been suppressed completely.
Matte, Robert. Bulgaria: Unhappy Satellite. // Military Review. - July 1963.