Battle of Kolubara their respective commands, and the 5th and 6th armies were merged into a single 5th Army of 95,000 men. 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
Austria-Este and the present heir is Franz, Duke of Bavaria. However, Francis V had decided to retain the Este name in the Habsburg family, and left most of his huge estate to his young cousin Archduke Franz Ferdinand of Austria, with certain conditions, one of which is that the heir and future heirs use the name of Este. The non-territorial property of the Este family thus fell to the line of Archduke Charles Louis, younger brother to then Emperor Francis Joseph, Austria-Este then becoming a sort of "secundogeniture" title within the Austrian imperial family. Although the first heir, Archduke Franz Ferdinand