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
German occupation of Luxembourg during World War I neutral state. The Luxembourg Crisis had seen Prussia thwart France's attempt to purchase the Grand Duchy from the Netherlands. Luxembourg's neutrality was accepted by Prussia's then-Chancellor, Otto von Bismarck, who boasted, "In exchange for the fortress of Luxembourg, we have been compensated by the neutrality of the country, and a guarantee that it shall be maintained in perpetuity." In June 1914, Archduke Franz Ferdinand, heir to the thrones of Austria-Hungary, was assassinated by pan-Slavic nationalists, leading to a sudden deterioration in relations between Austria-Hungary and Serbia. Austria-Hungary was supported by the German Empire, while Serbia had the backing of the