Recall of Baltic Germans

The Nazi–Soviet population transfers were population transfers between 1939 and 1941 of ethnic Germans (actual) and ethnic East Slavs (planned) in an agreement according to the German–Soviet Frontier Treaty between Nazi Germany and the Soviet Union.

One of Adolf Hitler's main goals during his rule was to unite all German-speaking people into one territory. There were hundreds of thousands of ethnic Germans living outside the borders of Germany, mostly in Central and Eastern Europe with the largest numbers being Germans from Russia. Most of these groups of German origin had lived outside Germany for hundreds of years, after emigrating eastwards between the 12th to 18th centuries.

Despite this, Hitler planned to move these people westwards into Nazi Germany. However, Hitler also believed that the 1937 borders and territories of Nazi Germany, i.e. before the "Anschluss" (annexation) of Austria and Sudetenland, were quite inadequate to accommodate this large increase in population. At this time, propaganda for more Lebensraum or "living space" greatly increased.

With the largest number of ethnic Germans living in Russia, Hitler knew that he could not resettle all these people without the full cooperation of Joseph Stalin and the Soviet Union. In late August 1939 (a week before the invasion of Poland and the start of World War II in Europe) Hitler sent his foreign minister Joachim von Ribbentrop to Moscow to arrange a pact of non aggression with the Soviet Union. This became known as the Molotov–Ribbentrop Pact. In reality Hitler's aim was to avoid Germany fighting on two fronts when the Second World War was about to begin a week later.

...
Wikipedia