On October 11, 1915, Prime Minister Vasil Radoslavov of Bulgaria issues a statement announcing his country’s entrance into the First World War on the side of the Central Powers.

Secretly courted by both sides in World War I as a potential ally in the tumultuous Balkan region, Bulgaria eventually decided in favor of the Central Powers. In his statement of October 11, 1916, Radoslavov argued that confronting the Allied powers—Britain, France and Russia—alongside Germany, Austria-Hungary and the Ottoman Empire was desirable not only for economic reasons, as the latter two countries were Bulgaria’s chief partners in trade, but also as a way for the country to defend itself against the aggression of Serbia, the Russian ally and major power in the Balkans that Radoslavov considered to be his country’s “greatest foe.”

“Today we see races that are fighting, not indeed for ideals, but solely for their material interests,” Radoslavov maintained. “The more, therefore, we are bound to a country in a material way, the greater is that country’s interest in our maintenance and increase, since thereby that one will profit who helps us and is tied to us by economic bonds… The figures show that our trade, our interests, and our economic life are inseparably linked with Turkey, Germany, and Austria-Hungary…”

Bulgaria acted quickly after its declaration of war, invading the Serbian province of Macedonia and in the process driving a wedge in front of Allied forces in Greece in their attempts to aid the Serbian army. In the summer of 1916, Bulgaria invaded and occupied a section of then-neutral Greece, mounting a major offensive in August that was only halted by British aerial and naval attacks. A stalemate ensued until 1918, when the Allies began to put more pressure on the Germans on the Western Front, forcing them to transfer a number of troops from the Salonika front—as the battlegrounds of northern Greece and Macedonia were known—where they had been aiding their Bulgarian allies. Disintegrating morale and growing discontent among the Bulgarian troops and on the home front were compounded by a new Allied offensive, launched in mid-September. On September 24, the Bulgarian government authorized its army’s commander to seek an armistice. Bulgaria formally exited World War I on September 29, 1918, having lost some 90,000 soldiers over the course of the conflict.