Fortress of Arad their honor. The most famous prisoner in the fortress of Arad was undoubtedly Gavrilo Princip, who on 28 June 1914 killed the heir to the throne of Austria-Hungary, Archduke Franz Ferdinand and his wife, Sophie, in Sarajevo, which led to the outbreak of World War I. About the inhuman conditions in which prisoners were held in the fortress of Arad warned Ştefan Cicio Pop, deputy of the Romanian National Party in an interpellation to the Hungarian parliament in Budapest during 1917. After the first World War, the fortress was occupied by allied Serbian and French troops under French command, until
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