Franz Joseph I of Austria the Empire on 6 October 1908. However a diplomatic crisis erupted, as both the Serbs and the Italians demanded compensation for the annexation, which the Austro-Hungarian government refused to entertain. The incident was not resolved until the revision of the Treaty of Berlin in April 1909, exacerbating tensions between Austria-Hungary and the Serbs. On 28 June 1914 Franz Joseph's nephew and heir Archduke Franz Ferdinand, and his morganatic wife Sophie, Duchess of Hohenberg, were assassinated by Gavrilo Princip, a Yugoslav nationalist of Serbian ethnicity, during a visit to Sarajevo. When he heard the news of the assassination, Franz Joseph said
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