After the entry into force of the Four-Power Agreement from 1971, the two German states began negotiations over a Basic Treaty. As for the Transit Agreement of 1972, the discussions were led by the Under-Secretaries of State Egon Bahr (for the Federal Republic of Germany) and Michael Kohl (for the German Democratic Republic). As part of the Ostpolitik of Chancellor Willy Brandt, the treaty was signed on 21 December 1972 in East Berlin.