Kingdom of Bulgaria
The Kingdom of Bulgaria proclaimed full independence from the Ottoman Empire on 5 October 1908, when Prince Ferdinand I took the title of tsar; its capital was Sofia. Bulgaria fought in both Balkan Wars, sided with the Central Powers in the First World War and lost territory under the Treaty of Neuilly in 1919. Under Tsar Boris III the country joined the Axis in 1941. The Red Army entered Bulgaria in 1944, and the monarchy was abolished by referendum in 1946.