Enter Bulgaria, Stage East

Bulgaria was not happy with the status quo at the end of the Second Balkan War.  Nearly all the land she had gained in the First Balkan War had been shifted away, and Tsar Ferdinand had felt forced to sign the 1913 Treaty of Bucharest agreeing to those terms.

So it was no real surprise when, on 14 October 1915, Bulgaria declared war on Serbia and entered the conflict on the side of the Central Powers, who had promised them a full reckoning of the land they believed was theirs.