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
Emperor of Austria in 1875. As Ferdinand I had no sons, his brother Francis Charles would have become emperor, but was persuaded by his wife to pass over the right of succession to their son, Francis Joseph. He accepted the duty of the Emperor of Austria without having been Crown Prince or "Thronfolger" before. Francis Joseph's only son Rudolf committed suicide in 1889, Francis Joseph's brother Karl Ludwig died in 1896. Karl Ludwig's son Franz Ferdinand became heir presumptive to the throne. He was assassinated in Sarajevo, Bosnia in 1914; due to his morganatic marriage, his son had no rights to the throne.