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
Serbian nationalism some Štokavian-speaking peoples to call themselves names other than Serbs. Ilija Garašanin was another early proponent of Serbian nationalism and a proponent of a Greater Serbia - a Serbian state whose borders were extended to include all Serbs in the Balkan region. After Serbia was recognized as an independent state in 1878, both South Slavs and the Serbian government considered their peoples in Habsburg-ruled Austria-Hungary to be under occupation resulting in increasing antagonism between Serbia and Austria-Hungary from the late 19th century to the early 20th century. In 1914 Austrian Archduke Franz Ferdinand was assassinated by Bosnian Serb revolutionary Gavrilo