Nearly 102 years ago, the Bulgarians entered the Great War on the side of the Central Powers.  While it began the 20th century as a client state of Russia it had become increasingly alienated from its patron.  As a member of the Balkan League it found itself in an unlikely alliance of Balkan countries.  The desire to, well, balkanize, the Ottoman Empire was a shared goal but the countries had very little else in common, and all wanted to expand into the same areas.  Not surprisingly its membership in the Balkan League did not last and it found itself being attacked and quickly defeated by the other members along with the Ottoman Empire, and Romania, always looking to capitalize on the belligerence of others.

When war broke out in 1914 the Bulgarians declared themselves neutral, having exhausted themselves in the two Balkan Wars; popular opinion supported this decision wholeheartedly.  However, much like Italy, they were in a desirable geographical position and both sides sought its support.  In this instance, the Central Powers were willing to make more expansive promises to Bulgaria.  At the same time, the Allies were engaged in both threatening and promising Bulgaria: on 4 October, an Allied ultimatum regarding the removal of German officers from Bulgaria seemed to seal the deal.  The next day they withdrew their diplomatic staff from Bulgaria.

On 14 October, Bulgaria declared war on Serbia and began an invasion that tipped the balance for the rest of 1915 and most of 1916.  The Bulgarians were successful in their fight against Serbia and Romania.  Since the Bulgarians were not in need of much support, this wartime alliance was perhaps the most beneficial one for the Germans, who were constantly sending men and materials to the Habsburg and Ottoman armies.

Like many other battlefields, the Balkans turned into a war of attrition, and here Bulgaria was at a disadvantage.  Although the final result of the war was far from sure in 1917, the Bulgarian army and people began to grow tired of war – after all, they had been fighting off and on since 1913.

The end result for the Bulgarians would not be what they hoped, and they lost more land as a result of their gamble.