[1] The remaining former German citizens were primarily autochthons, who were allowed to stay in post-war Poland after declaring Polish nationality in a verification process.
In addition to those groups, a substantial number of Poles who never had German citizenship were emigrating to West Germany during the period of the People's Republic of Poland for political and economic reasons.
[citation needed] After 1945, ethnic deportation was used to create a homogeneous nation within the new borders of the People's Republic of Poland (which contained a substantial amount of territory that was once part of Germany).
[4][5] Although the Potsdam Agreement left the final decision about the border shift to a future peace treaty, the Polish government (which had implemented pre-Potsdam expulsions from the Oder–Neisse line area)[6] interpreted it as final decision which would be confirmed by the peace treaty.
Many former German citizens willing to settle in West Germany were not allowed to leave Poland until the Polish October of 1956.
This event, which marked the decline of Stalinism in Poland, allowed many to leave the country in a family-reunification process.
[17] Most emigrants were autochthones, who decided to start a new life in Germany due to cross-border family ties and for economic and political reasons.
[18] During the late 1970s, West German chancellor Willy Brandt's policy of Ostpolitik led to a rapprochement with Poland and relations were normalized in the Treaty of Warsaw.
This led to further agreements between Brandt and Polish leader Edward Gierek, which concluded in Helsinki during the third phase of the Conference on Security and Co-operation in Europe.
Many, especially if they were born after 1945, were unable to speak German; at home they spoke their regional dialect, and at school they were taught Polish and Russian.
They are characterised by deep national pride, and actively participate in Polish cultural and political life in Germany; however, few returned to Poland after the fall of communism in 1989.