The conquest of Poland by the Third Reich afforded Nazi racial ideologues their first real opportunity of restructuring a sizeable population and geographic area outside the boundaries of the Reich on racial grounds. The expansion eastward, although compromised by the need to come to an agreement with the USSR on the division of Poland, as set forth in the Nazi-Soviet Pact (24 August, 1939), revised on September 28, 1939, provided Germany with an extra 188,000 square kilometres of territory within which to experiment with demographic reorganization. The conquered territory included approximately 20 million people, of whom 650,000 were ethnic Germans and 2.6 million were Jews. A portion of the conquered territories had previously been under German control, but ceded to Poland under the terms of the Versailles Treaty, June 1919. These, along with territory that had not previously been German were incorporated into the Reich either by attachment to existing provinces (Eastern Prussia) or the creation of new administrative areas (Reichsgau Danzig-West Prussia and Reichsgau Posen, which after January 1940 was named Warthegau). The eastern part of German occupied Poland was not incorporated in the Reich. From August 1940 it was known as the General Government, its seat of government being the old Polish capital, Krakow. Hitler appointed Dr Hans Frank as Governor General of the occupied Polish territories, that is, those territories not incorporated directly in the Reich.
The initial aspiration of the racial planners, especially the Reichsführer of the SS, Heinrich Himmler, and Alfred Rosenberg, one of the foremost Nazi race theoreticians, was to move Poles and Jews out of the incorporated territories and into the General Government area. The ethnic Germans residing in occupied Poland, and the Baltic states, would be resettled in these areas. [In progress]