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 Wilhelm Franz of Austria Archduke Wilhelm Franz of Austria Archduke Wilhelm Franz Karl of Austria-Teschen (German: Erzherzog Wilhelm Franz Karl von Habsburg-Lothringen, 21 April 1827 – 29 April 1894) was an Archduke of Austria from the House of Habsburg. He was born in Vienna as the son of Archduke Charles, Duke of Teschen (1771–1847) and Princess Henrietta of Nassau-Weilburg (1797–1829). He was a grandson of Leopold II (1747–1792) and nephew of Franz II (1768–1835), the last two Holy Roman Emperors. He held the office of Grand Master of the Teutonic Knights from 1863 until his death in 1894. He gained the rank of "Feldzeugmeister"