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
Archduke Friedrich, Duke of Teschen of the ruling house, Friedrich adopted a military career, and served creditably for many years as commandant of the V. (Pressburg) Corps. Subsequently, commander-in-chief of the Austrian Landwehr (militia) and army inspector, he became, after the murder of the heir to the throne, Archduke Franz Ferdinand, inspector-general of the Austro-Hungarian Army. In World War I, he was —from the dynastic point of view —as grandson of the victor of Aspern, Archduke Charles, and as nephew of the victor of Custoza, Archduke Albert, the predestined head of the armed forces of Austria-Hungary; and on 11 July 1914 Friedrich was appointed supreme