Gorbachev’s agreement also meant that the so-called Two-plus-Four Treaty could be signed in September 1990. Within that framework the Soviet Union, the United States, France and the United Kingdom as well as the representatives of the two German states confirmed the unification of Germany consisting of the territories of the former GDR, the Federal Republic and Berlin. Germany’s external borders were recognized as definitive. Bonn and Warsaw concluded a separate treaty to take account of Poland’s special security needs in the light of history. Both agreed to respect each other’s territorial integrity and sovereignty.

The ratification of the Unification Treaty and the Two-plus-Four Treaty marked the termination of the rights and responsibilities of the four victorious powers “with respect to Berlin and Germany as a whole”. Germany thus regained the complete sovereignty over its internal and external affairs which it had lost 45 years previously with the fall of the National Socialist dictatorship.