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
Emperor of Austria in 1875. As Ferdinand I had no sons, his brother Francis Charles would have become emperor, but was persuaded by his wife to pass over the right of succession to their son, Francis Joseph. He accepted the duty of the Emperor of Austria without having been Crown Prince or "Thronfolger" before. Francis Joseph's only son Rudolf committed suicide in 1889, Francis Joseph's brother Karl Ludwig died in 1896. Karl Ludwig's son Franz Ferdinand became heir presumptive to the throne. He was assassinated in Sarajevo, Bosnia in 1914; due to his morganatic marriage, his son had no rights to the throne.