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 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