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
Ferdinand of Austria-Este Ferdinand of Austria-Este Archduke Ferdinand Karl of Austria-Este (1 June 1754 – 24 December 1806) was a son of Holy Roman Emperor Franz I and Maria Theresa of Austria. He was the founder of the House of Austria-Este and Governor of the Duchy of Milan between 1765 and 1796. He was also designated as the heir to the Duchy of Modena and Reggio, but he never reigned, owing to the Napoleonic Wars. Ferdinand was born at the Schönbrunn Palace in Vienna as the fourth son and fourteenth child of the Holy Roman Emperor Franz I and of his wife, Maria