Gavrilo Princip (Serbian Cyrillic: Гаврило Принцип, ; 25 July 1894 – 28 April 1918) was the man who assassinated Archduke Franz Ferdinand of Austria and his wife, Sophie, Duchess of Hohenberg, in Sarajevo on 28 June 1914. Princip and his accomplices were arrested and implicated a number of members of the Serbian military, leading Austria-Hungary to issue a démarche to Serbia known as the July Ultimatum. This set off a chain of events that led to the First World War. Princip was a Yugoslav nationalist associated with the movement Mlada Bosna (Young Bosnia) which predominantly consisted of Serbs, but also Bosniaks and Croats. During his trial he stated "I am a Yugoslav nationalist, aiming for the unification of all Yugoslavs, and I do not care what form of state, but it must be free from Austria."
Read more about Gavrilo Princip: Early Life, Assassination of The Archduke Franz Ferdinand, Capture and Imprisonment