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 Karl Ferdinand of Austria He became a Lieutenant Field Marshal of the Austrian Army. In Vienna, on 18 April 1854, Karl Ferdinand married his first cousin, Archduchess Elisabeth of Austria (1831–1903), the widow of Archduke Ferdinand of Austria-Este, and the daughter of Archduke Joseph of Austria, Palatine of Hungary. They had six children: Archduke Karl Ferdinand of Austria Archduke Karl Ferdinand of Austria (Vienna, 29 July 1818 – Gross Seelowitz (Židlochovice Castle), 20 November 1874) was the second son of Archduke Charles, Duke of Teschen (1771–1847) and Princess Henrietta of Nassau-Weilburg, and the maternal grandfather of King Alfonso XIII of Spain. A son of