Well that and many of the Germans were asked to move to Russia by various Czars through the centuries.
These Czars being, of course, Germans. -_-
Not so common post-1990. It was back in the 50s, 60s, and 70s.
Was not a formal recognition, but sailed very close to one and almost toppled the Brandt government for that reason.
Incidentally, there was a change in the way boundaries were depicted in West German atlases in the early 70s. Til then the 1937 borders - including the existence of Danzig - were shown like ordinary borders, with the de facto borders - both the eastern and the western border of the GDR, and the line through East Prussia - shown as lighter, broken lines. Afterwards, both sets of boundaries were made to look different from borders everywhere else.
