Causes of World War Two Long term causes of World War Two Manchuria 1931 Abyssinia 1935 Haile Selassie and the League of Nations Germany and rearmament Rhineland 1936 Italy and Germany 1936 to 1940 The Hossbach Conference of 1937 The Hossbach Memorandum Austria and 1938 The Czech Crisis of 1938 Scrap of Paper 1939 The British Declaration of War Germany 1939 Public Opinion and Appeasement in 1938