The main causes of World War I, which broke out unexpectedly in central Europe in summer 1914, included many factors, such as the conflicts and hostility of the four decades leading up to the war. Militarism, alliances, imperialism, and ethnic nationalism played major roles. However the immediate origins of the war lay in the decisions taken by statesmen and generals during the Crisis of 1914, which was sparked by the assassination of Archduke Franz Ferdinand (the Archduke of Austria Hungary) by a Serbian secret organization, the Black Hand.