World War Central Powers

Austria-Hungary

1914

Austria-Hungary declares war on Serbia. On July 28, 1914, one month to the day after Archduke Franz Ferdinand of Austria and his wife were killed by a Serbian nationalist in Sarajevo, Austria-Hungary declares war on Serbia, effectively beginning the First World War.

Germany

1915

it did not enter the war until other countries had already declared war on one another. The first country to declare war in WWI was Austria-Hungary. That country issued an ultimatum to Serbia after the assassination of the Austro-Hungarian Archduke Franz Ferdinand.

Bulgaria

1915

In the Second Balkan War, Bulgaria was at war with Serbia, and lost, so when WWI started, and Germany allied itself with Austria-Hungary against Serbia, Bulgaria joined in on the German side.

Ottoman Empire

1918

Ottoman forces fought the Entente in the Balkans and the Middle Eastern theatre of World War I. The Ottoman Empire's defeat in the war in 1918 was crucial in the eventual dissolution of the empire in 1921.