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
Archduke Otto of Austria (1865–1906) of Emperor Franz Joseph I of Austria; and Karl Ludwig became heir presumptive to the Austro-Hungarian throne when his nephew Crown Prince Rudolf died in 1889. Although a newspaper account claimed that Karl Ludwig renounced his rights to the throne that same year (1889) in favour of his eldest son, Franz Ferdinand, that story is not certain. On the death of Karl Ludwig in May 1896, Otto's brother Franz Ferdinand did indeed become heir presumptive to the Austro-Hungarian throne. At the time of their father's death, Franz Ferdinand had been ill with tuberculosis and there was speculation that Franz Ferdinand