text: Montenegro declared war on 6 August 1914. Bulgaria, however, stood aside before eventually joining the Central Powers in 1915, and Romania joined the Allies in 1916.
  In 1916 the Allies sent their ill-fated expedition to Gallipoli in the Dardanelles, and in the autumn of 1916 they established themselves in Salonika, establishing front. However, their armies did not move from front until near end of the war, when they marched up north to free territories under rule of Central Powers.
  Bulgaria
  Bulgaria, the most populous of the Balkan states with 7 million people sought to acquire Macedonia but when it tried it was defeated in 1913 in the Second Balkan War. In 1914 Bulgaria stayed neutral.  However its leaders still hoped to acquire Macedonia, which was controlled by an ally, Serbia. In 1915 joining the Central Powers seemed the best route. Bulgaria mobilized a very large army of 800,000 men, using equipment supplied by Germany. The Bulgarian-German-Austrian invasion of Serbia in 1915 was a quick victory, but by the end of 1915 Bulgaria was also fighting the British and French—as well as the Romanians in 1916 and the Greeks in 1917.  Bulgaria was ill-prepared for a long war; absence of so many soldiers sharply reduced agricultural output. Much of its best food was smuggled out to feed lucrative black markets elsewhere.