Following a Soviet declaration of war and a coup by the Fatherland Front, Bulgaria abruptly switched sides, declaring war on its former ally Germany. Bulgarian troops, which had occupied parts of Greece and Yugoslavia, turned against retreating German forces. The reversal reflected the rapid collapse of Axis fortunes in the Balkans as Soviet armies advanced.
Bulgaria's wartime position had always been uneasy—it joined the Axis but notably refused to send troops to fight the Soviet Union or to deport its own Jewish population, saving nearly 50,000 lives even while allowing deportations from occupied Macedonia and Thrace. When the Red Army crossed into Romania and then approached Bulgarian territory in early September 1944, the fragile pro-German government collapsed within days.
The Fatherland Front, a coalition including communists, agrarians, and military officers, seized power and immediately reoriented the country. Bulgarian units that had spent years as occupying forces in Yugoslav and Greek territory suddenly found themselves ordered to fight the German army retreating through the Balkans. The switch spared Bulgaria the devastation experienced elsewhere in the region but placed it firmly within the Soviet sphere for the next 45 years.