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
Archduke Wilhelm Franz of Austria attributed to a concussion on the brain. The archduke was 67 years old. Archduke Wilhelm Franz of Austria Archduke Wilhelm Franz Karl of Austria-Teschen (German: Erzherzog Wilhelm Franz Karl von Habsburg-Lothringen, 21 April 1827 – 29 April 1894) was an Archduke of Austria from the House of Habsburg. He was born in Vienna as the son of Archduke Charles, Duke of Teschen (1771–1847) and Princess Henrietta of Nassau-Weilburg (1797–1829). He was a grandson of Leopold II (1747–1792) and nephew of Franz II (1768–1835), the last two Holy Roman Emperors. He held the office of Grand Master of the Teutonic Knights