The immediate cause was Germany invading Poland on September 1, 1939, and Britain and France declaring war on Germany on September 3, 1939. Problems arose in Weimar Germany that experienced strong currents of revanchism after the Treaty of Versailles that concluded its defeat in World War I in 1918.
Problems arose in Weimar Germany that experienced strong currents of revanchism after the Treaty of Versaillest hat concluded its defeat in World War I in 1918. Dissatisfactions of treaty provisions included the demilitarizationof the Rhineland, the prohibition of unification with Austria (including the Sudetenland) and the loss of German-speaking territories such as Danzig and Eupen-Malmedy despite Wilson’s Fourteen Points, the limitations on the Reichswehr making it a token military force, the war-guilt clause, and last but not least the heavy tribute that Germany had to pay in the form of war reparations, which became an unbearable burden after the Great Depression. The most serious internal cause in Germany was the instability of the political system, as large sectors of politically active Germans rejected the legitimacy of the Weimar Republic.
History 