Serbian Campaign of World War I Serbia, Montenegro, and Greece. When Bulgaria attacked both Serbia and Greece on 16 June 1913, it lost most of its Macedonian region to those countries, and additionally the Southern Dobruja region to Romania and Adrianople (the present-day city of Edirne) to Turkey in the 33-day Second Balkan War, which further destabilized the region. On 28 June 1914, Gavrilo Princip, a Bosnian Serb student and member of a multi-ethnic organisation of national revolutionaries called Young Bosnia, assassinated Archduke Franz Ferdinand of Austria, the heir to the Austro-Hungarian throne, in Sarajevo, Bosnia. The political objective of the assassination was the independence of
July Crisis reason for armed conflict, the dispute between Serbia and Austria-Hungary over the murdered heir, had already become a sidenote to a general European war. Austria-Hungary had annexed Bosnia and Herzegovina in 1908. Sarajevo was the provincial capital. Oskar Potiorek was the military commander and governor of the province. Emperor Franz Joseph ordered Archduke Franz Ferdinand, heir presumptive to the Austro-Hungarian throne, to attend military exercises due to be held in Bosnia. After the exercises, on 28 June 1914, Ferdinand toured Sarajevo with his wife, Sophie. Six armed irredentists, five Serbs and one Bosnian Muslim, coordinated by Danilo Ilić, lay in