Moscow Treaty, August 1970: FRG recognised post-1945 frontiers
Berlin Treaty, September 1971: unimpeded transit rights to West Berlin
Treaties with Poland, December 1970, and Czechoslovakia, June 1973, recognised 1945 borders
The Basic Treaty, December 1972: FRG gave up Hallstein Doctrine which said that if any state recognised the GDR, diplomatic relations would end.