History of Western civilization heir to the Austro-Hungarian throne, Franz Ferdinand, and he was assassinated on 28 June 1914 by a Yugoslav nationalist named Gavrilo Princip in the city of Sarajevo, at the time part of the Austro-Hungarian Empire. Although Serbia agreed to all but one point of the Austrian ultimatum (it did not take responsibility in planning the assassination but was ready to hand over any subject involved on its territory), Austria-Hungary was more than eager to declare war, attacked Serbia and effectively began World War I. Fearing the conquest of a fellow Slavic Orthodox nation, Russia declared war on Austria-Hungary. Germany responded
History of Russia (1892–1917) was Serbia's territorial rival in the region, and Germany remained the Ottoman Empire's protector. Russia tied itself more closely to Serbia than it had previously. The complex system of alliances and Great Power support was extremely unstable; among the Balkan parties harboring resentments over past defeats, the Serbs maintained particular animosity toward the Austro-Hungarian annexation of Bosnia and Herzegovina. In June 1914, a Serbian terrorist assassinated Archduke Franz Ferdinand, heir to the throne of Austria–Hungary, which then held the Serbian government responsible. Austria–Hungary delivered an ultimatum to Serbia. Serbia submitted to the first 2 of 3 cases of the ultimatum;