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
Archduke Joseph Árpád of Austria Archduke Joseph Árpád of Austria Archduke Joseph Árpád Benedikt Ferdinand Franz Maria Gabriel (; 8 February 1933 – 30 April 2017) was a member of the Hungarian Palatine branch of the House of Habsburg-Lorraine. He was born in Budapest, the son of Archduke Joseph Francis of Austria and his wife, Princess Anna of Saxony. He was the great-grandson of Archduchess Gisela of Austria. He received a degree in economics from the University of Lisbon. Joseph married Princess Maria von Löwenstein-Wertheim-Rosenberg, born 1935, daughter of Karl, 8th Prince of Löwenstein-Wertheim-Rosenberg and Carolina dei Conti Rignon. They married civilly on 25 August