Causes of World War I corrective." British Diplomat Arthur Nicolson wrote in May 1914, “Since I have been at the Foreign Office I have not seen such calm waters.” On 28 June 1914, Archduke Franz Ferdinand of Austria, heir presumptive to the Austro-Hungarian throne, and his wife, Sophie, Duchess of Hohenberg, were shot dead, by two gun shots in Sarajevo by Gavrilo Princip, one of a group of six assassins (five Serbs and one Bosniak) coordinated by Danilo Ilić, a Bosnian Serb and a member of the Black Hand secret society. The assassination is significant because it was perceived by Austria-Hungary as an existential challenge
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