The First World War By whl 1873 Bismarck started the alliance system 1881 Tunisian Incident 1882 Formation of the Triple Alliance 1898 Fashoda Incident 1899 First disarmament conference at Hague 1905 First Moroccan Crisis 1907 Formation of the Triple Entente 1907 Second disarmament conference at Hague 1908 Bosnian Crisis 1911 Second Moroccan Crisis 1912 First Balkan War 1913 Second Balkan War 1914 Sarajevo Incident 1914 Outbreak of the First World War 1915 Unrestricted submarine warfare adopted by Germany 1915 Entry of Italy 1917 Entry of U.S.A. 1918 Russian withdrawal from the War 1918 End of the First World War 1919 Paris Peace Conference 1919 Signing of the Treaty of Versailles 1920 Formation of the League of Nations