The Federal Republic of Germany’s opening of relations with the Eastern bloc in the 1970s. It was a reversal of West Germany’s refusal to recognize the legitimacy of the German Democratic Republic (East Germany), as propounded in the Hallstein Doctrine (1955). The policy of Ostpolitik was pursued with particular vigour by Willy Brandt, as Chancellor of the Federal Republic. A General Relations Treaty (1972) normalized relations between the two Germanys, while treaties between West Germany and both the Soviet Union and Poland gave formal recognition to the Oder-Neisse frontier (1970–72).