With Bosnia-Herzegovina firmly in Austro-Hungarian hands, Serbia and several other Balkan states turned to forcing the Ottoman Empire from southeastern Europe. The ensuing Balkan Wars, which lasted from 1912 until 1913, saw Serbia take possession of Kosovo and Macedonia. 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 the following day, marking the beginning of the First World War.