Starting on November 27, 1970, Egon Bahr (left), State Secretary in the Federal Chancellery, and Michael Kohl (right), State Secretary in the GDR Council of Ministers, began a series of discussions on regulating the relationship between the two German states, rotating between Bonn and East Berlin. After the former occupying powers signed the Quadripartite Agreement on Berlin on September 3, 1971, the government of the Federal Republic and the Berlin Senate concluded various supplemental agreements: a protocol on postal and telecommunications issues (September 30, 1971), a transit agreement on traffic into and out of West Berlin (December 17, 1971), and an agreement between the Berlin Senate and the GDR government on the flow of travelers and visitors in and out of West Berlin and on enclaves (December 20, 1971).