Our Series on World War One takes us to the Balkan Region. Bulgaria entered World War I on the side of the Central Powers, Germany, Austria and the Ottoman Empire, in 1915. Since the Second Balkan War of 1913, Bulgaria had outstanding territorial disputes with two of its neighbours, Serbia and Greece.
The Central Powers promised Bulgaria a large portion of Southeastern Serbia that would allow the alliance to control a rail line from Vienna to Constantinople. The Bulgarians were successful at first in encroaching into Serbian territory, but the war became more static, like it was on all other fronts. By 1918, the Central Empires were collapsing and the Western Powers intervened massively in the Balkans, forcing Bulgaria to sign an armistice in September of that year.
The peace treaty that followed, signed in Neuilly on November 27, 1919, saw some loss of territory for Bulgaria in five different areas. Three small patches of lands along the Serbian border were awarded to the new country of Yugoslavia in order to consolidate their defence lines. The region around Strumitsa in the Southwest was also awarded to Yugoslavia. Finally, Bulgaria's Aegean Sea access in Thrace was given to Greece, giving it a direct land border with Turkey.
Discontentment about this situation would push Bulgaria one more time into the arms of Germany at the beginning of World War II, with temporary occupation of large territories in Northern Greece and Southern Yugoslavia, but those gains were once again reversed at the end of the conflict.
Bulgaria's WW1 Territorial Losses
