Battle of Cer On 28 June 1914, Bosnian Serb student Gavrilo Princip assassinated Archduke Franz Ferdinand of Austria in Sarajevo. The assassination precipitated the July Crisis, which led Austria-Hungary to issue an ultimatum to Serbia on 23 July on suspicion that the assassination had been planned in Belgrade. The Austro-Hungarian government made the ultimatum intentionally unacceptable to Serbia, and it was indeed rejected. The Austro-Hungarians declared war on Serbia on 28 July and that same day the Serbs destroyed all bridges on the Sava and Danube rivers in order to prevent the Austro-Hungarians from using them during any future invasion. Belgrade was shelled
Oskar Potiorek Oskar Potiorek Oskar Potiorek (20 November 1853 – 17 December 1933) was an officer of the Austro-Hungarian Army, who served as Governor of Bosnia and Herzegovina from 1911 to 1914. He was a passenger in the car carrying Archduke Franz Ferdinand of Austria and his wife Duchess Sophie of Hohenberg when they were assassinated in Sarajevo on 28 June 1914. In the following World War I, Potiorek commanded the Austro-Hungarian forces in the Serbian Campaign of 1914/15. Born in Bad Bleiberg, Carinthia the son of a mining official, Potiorek attended the Imperial and Royal military institute of technology and the