Bulgarian Memorial Medal of the European War 1915-1918
The Kingdom of Bulgaria participated in World War I on the side of the Central Powers from 14 October 1915, when the country declared war on Serbia, until 30 September 1918, when the Armistice of Thessalonica was signed and came into effect.
In the aftermath of the Balkan wars Bulgaria found itself isolated on the international scene, surrounded by hostile neighbors and deprived of the support of the Great Powers. Anti-Bulgarian sentiments were especially strong in France and Russia, whose political circles blamed the country for the dissolution of the Balkan League. This and the failure of Bulgarian foreign policy turned revanchism in a focal point for the country's external relations.
When the First World War erupted in August 1914 Bulgaria was still recovering from the negative economic and demographic impact of the recent wars and avoided direct involvement in the new conflict by declaring neutrality. The strategic geographic location and strong military made the country a desired ally by both warring sides but Bulgarian aspirations were difficult to satisfy because they included territorial claims against four Balkan countries. As the war progressed the Central Powers found themselves in a better position to fulfill Bulgarian demands and persuaded the country to join their cause in September 1915.
Despite being the smallest member of the alliance in area and population Bulgaria made vital contributions to the common war effort. Its entry to the war was the death knell to Serbia and Romania, and ensured the continuous Ottoman war effort by opening the way for much needed German material assistance.
Despite that initially the war was characterized with highly successful campaigns of rapid movements in 1915 and 1916, once most Bulgarian territorial aspirations had been satisfied it degraded into a state of trench attrition on both the Northern and the Southern Front This prolonged period substantially weakened the economy, created various supply problems and reduced the health and morale of the troops on the front lines. Under these circumstances the Allied armies in Greece, composed of contingents from almost all Entente countries, managed to break the Macedonian Front and cause the rapid collapse of part of the Bulgarian Army, which took the form of an open military rebellion and proclamation of a republic by the rebellious troops at Radomir. Bulgaria was forced to seek and accept an armistice on 30 September 1918. For a second time in half a decade the country had been led to a national catastrophe for which Tsar Ferdinand I assumed responsibility, abdicated and left Bulgaria to his heir on 3 October 1918.
The formal conclusion of Bulgaria's participation in World War I was marked by the signing of the Treaty of Neuilly in 1919, according to which the country had to return all occupied territories, cede even more of its land and pay heavy reparations.