Treaty of Versailles signed 28 June 1919
The assassination on 28 June 1914 of Archduke Franz Ferdinand of Austria, the heir to the throne of Austria-Hungary, is seen as the immediate trigger of the war, though long-term causes, such as imperialistic foreign policy, played a major role. Ferdinand's assassination at the hands of Serbian nationalist Gavrilo Princip resulted in demands against the Kingdom of Serbia.[6] Several alliances that had been formed over the past decades were invoked, so within weeks the major powers were at war; with all having colonies, the conflict soon spread around the world.
By the war's end, four major imperial powers—the German, Russian, Austro-Hungarian and Ottoman Empires—had been militarily and politically defeated, with the last two ceasing to exist.[7] The revolutionised Soviet Union emerged from the Russian Empire, while the map of central Europe was completely redrawn into numerous smaller states.[8] The League of Nations was formed in the hope of preventing another such conflict. The European nationalism spawned by the war, the repercussions of Germany's defeat, and of the Treaty of Versailles would eventually lead to the beginning of World War II in 1939.[9]
In the 19th century, the major European powers had gone to great lengths to maintain a balance of power throughout Europe, resulting by 1900, in a complex network of political and military alliances throughout the continent.[2] These had started in 1815, with the Holy Alliance between Germany (then Prussia), Russia, and Austria–Hungary. Then, in October 1873, German Chancellor Bismarck negotiated the League of the Three Emperors (German Dreikaiserbund) between the monarchs of Austria–Hungary, Russia and Germany. This agreement failed because Austria–Hungary and Russia could not agree over Balkan policy, leaving Germany and Austria–Hungary in an alliance formed in 1879, called the Dual Alliance. This was seen as a method of countering Russian influence in the Balkans as the Ottoman Empire continued to weaken.[2] In 1882, this alliance was expanded to include Italy in what became the Triple Alliance.[10]