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
Assassination of Archduke Franz Ferdinand advocate of increased federalism and widely believed to favor trialism, under which Austria-Hungary would be reorganized by combining the Slavic lands within the Austro-Hungarian empire into a third crown. A Slavic kingdom could have been a bulwark against Serb irredentism, and Franz Ferdinand was therefore perceived as a threat by those same irredentists. Princip later stated to the court that preventing Franz Ferdinand's planned reforms was one of his motivations. The day of the assassination, June 28 (June 15 in the Julian calendar), is the feast of St. Vitus. In Serbia, it is called Vidovdan and commemorates the 1389 Battle