English: Gavrilo Princip in his prison cell at the Terezín fortress, 1914. The same year, Princip had killed Archduke Franz Ferdinand of Austria and his wife Sophie of Hohenberg. On 28 June 1914, Princip and five more assassins of the Black Hand society planned to kill Franz Ferdinand for the creation of a Yugoslavian state. The result, however, led to the First World War with Austria-Hungary’s declaration of war on Serbia. Princip was too young to receive the death penalty, so received the maximum sentence of twenty years in prison. Because of being held in harsh conditions, he contracted tuberculosis and died on 28 April 1918 at Terezín short before the war had ended.