Subsequently, under the Ostpolitik, the Federal Republic in the early 1970s sought to end hostile relations with the countries of the Eastern Bloc, in the course of which it negotiated in 1972 a Basic Treaty with the GDR, recognising it as one of two German states within one German nation, and relinquishing any claim to de jure sovereign jurisdiction over those parts of Germany within the GDR. The Treaty was challenged in the Federal Constitutional Court, as apparently contradicting the overriding aspirations of the Basic Law for a unified German state; but the Treaty's legality was upheld by the court, heavily qualified by a reassertion of the claim that the German Reich continued to exist as an 'overall state' such that the duty to strive for future German unity could not be abandoned, albeit that without any institutional organs of itself the Reich was currently not capable of action.[35] The Federal Republic was indeed identical with the German Reich; but this was a 'partial identity' that stopped at the boundaries of the Federal Republic and did not extend retrospectively to the period 1945-1949 before the Federal Republic had come into being.