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–Russia relations Treaty of Berlin. While Russia eventually backed down, relations between the two Empires were permanently damaged. The lasting result was bitter enmity between Austria-Hungary on one side and Serbia and Russia on the other. Following the assassination of Archduke Franz Ferdinand of Austria by Serb nationalists of the Black Hand secret society on 28 June 1914, Austria delivered the July Ultimatum to Serbia demanding that the Austrian police and military have the right to enter Serbia. Serbia rejected the ultimatum and on 28 July 1914, Austria-Hungary declared war on Serbia. On August 6, the Emperor Franz Joseph signed the Austro-Hungarian