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
July Crisis reason for armed conflict, the dispute between Serbia and Austria-Hungary over the murdered heir, had already become a sidenote to a general European war. Austria-Hungary had annexed Bosnia and Herzegovina in 1908. Sarajevo was the provincial capital. Oskar Potiorek was the military commander and governor of the province. Emperor Franz Joseph ordered Archduke Franz Ferdinand, heir presumptive to the Austro-Hungarian throne, to attend military exercises due to be held in Bosnia. After the exercises, on 28 June 1914, Ferdinand toured Sarajevo with his wife, Sophie. Six armed irredentists, five Serbs and one Bosnian Muslim, coordinated by Danilo Ilić, lay in