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
Assassination of Archduke Franz Ferdinand wife planned to visit Sarajevo to open the state museum in its new premises there. Duchess Sophie, according to their eldest son, Duke Maximilian, accompanied her husband out of fear for his safety. As Sophie, although of high aristocratic birth, was not from a dynastic family, her union with the Habsburg heir presumptive could only be a morganatic marriage. Emperor Franz Joseph had only consented to their marriage on the condition that their descendants would never ascend the throne. The 14th anniversary of their marriage fell on 28 June. As historian A. J. P. Taylor observes: Franz Ferdinand was an