war In the 19th century, the rise of romantic nationalism in Germany had led to the concepts of Pan-Germanism and Drang nach Osten, which in part gave rise to the concept of Lebensraum. German nationalists used the existence of large German minorities in other countries as a basis for territorial claims. Many of the propaganda themes of the Nazi regime against Czechoslovakia and Poland claimed that the ethnic Germans (Volksdeutsche) in those territories were persecuted. There were many incidents of persecution of Germans in the interwar period, including the French invasion of Germany proper in the 1920s. The German state was weak until 1933 and could not even protect itself under the terms of the Treaty of Versailles. The status of ethnic Germans, and the lack of contiguity of German majority lands resulted in numerous repatriation pacts whereby the German authorities would organize population transfers (especially the Nazi-Soviet population transfers arranged between Adolf Hitler and Joseph Stalin, and others with Benito Mussolini's Italy) so that both Germany and the other country would increase their homogeneity. However, these population transfers were considered but a drop in the pond, and the "Heim ins Reich" rhetoric over the continued disjoint status of enclaves such as Danzig and Königsberg was an agitating factor in the politics leading up to World War II, and is considered by many to be among the major causes of Nazi aggressiveness and thus the war. Adolf Hitler used these issues as a pretext for waging wars of aggression against Czechoslovakia and Poland. Nazi settlement concepts during World War II (1939–45) The status of ethnic Germans, and the lack of contiguity resulted in numerous repatriation pacts whereby the German authorities would organize population transfers (especially the Nazi–Soviet population transfers arranged between Adolf Hitler and Joseph Stalin, and others with Benito Mussolini's Italy) so that both Germany and the other country would increase their "ethnic homogeneity". Resettlement of Germans from the Baltic States and Bessarabia German populations affected by the population exchanges were primarily the Baltic Germans and Bessarabia Germans and others who were forced to resettle west of the Curzon Line. The Molotov–Ribbentrop Pact had defined "spheres of interest", assigning the states between Nazi Germany and the Soviet Union to either one of those. Except for Memelland, the Baltic states were assigned to the Soviet Union, and Germany started pulling out the Volksdeutsche population after reaching respective agreements with Estonia