Bulgaria during World War I 28 June 1914, Gavrilo Princip, a Bosnian-Serb student and member of Young Bosnia, assassinated the heir to the Austro-Hungarian throne, the Archduke Franz Ferdinand of Austria in Sarajevo, Bosnia. This began a period of diplomatic manoeuvring between Austria-Hungary, Germany, Russia, France and Britain called the July Crisis. Wanting to end Serbian interference in Bosnia conclusively, Austria-Hungary delivered the July Ultimatum to Serbia, a series of ten demands that were intentionally meant to be unacceptable in order to precipitate a war with Serbia. When Serbia acceded to only eight of the ten demands levied against it in the ultimatum, Austria-Hungary declared
Austria–Serbia relations of Serbian revolts during the 1848 Revolutions were not opposed by the Habsburg rulers. Serbian claims were not recognized by Hungary was eventually placated with the Austro-Hungarian Compromise of 1867, further angering Serbian nationalists. One notable flare-up between the two countries was the 1906-1909 economic conflict known as the Pig War which occurred simultaneously with the diplomatic and military crisis over the Austrian annexation of Bosnia. Ultimately, the tensions between the two countries could not withstand the strain of Assassination of Archduke Franz Ferdinand of Austria by Bosnian Serbs in 1914. Following the July Crisis, Austria invaded Serbia to punish