In accordance with the Yalta conference, by the end of the war Germany was split in 1945, into four occupation zones – a French administrative zone to the west; a British zone of administration to the northwest; an American administrative zone to the south; and a Soviet zone of administration to the east. At the time the divisions were not meant to be political but merely temporary boundaries of an imminently unified Germany. Between 1946 and 1949, three of these arbitrary zones started to merge. Initially, in December 1946, the zones under British and American occupation were combined and Bizonia was formed. In 1949, France agreed to merge the French administrative zone to form Trizonia. The pre-war German states came to be replaced by Länder, the new administrative states. The Soviet zone, however, remained distinct and separate.

By 1947, the commencement of the Cold War between the US-led Western Bloc and the USSR–dominated Eastern Bloc led to an escalation in political and military tensions. This further inhibited any negotiation between the two nations with regard to a merger of what had now become two parts of Germany – commonly called East Germany and West Germany. The West German Parliamentary Council convened on May 23, 1949 and formally declared the establishment of the Federal Republic of Germany. The Soviet Union was quick to react to the establishment of West Germany. In October 1949, the German Democratic Republic (East Germany) was officially established. The young Federal Republic built close links with the western democracies. It was one of the founding members of the European Coal and Steel Community in 1951 and one of the six countries that signed the Treaty establishing the European Economic Community – today’s European Union.

For the next 41 years, Germany remained divided with cold war. East Germany  sealed off the “zonal border” and built a wall throughout the city, ending free access to West Berlin. However over a period, economic conditions worsened in East Germany necessitating a breakdown of the strict sanctions and barriers and the Berlin Wall was demolished in 1989, uniting Germany again.

 

Reference:

http://www.mapsofworld.com/on-this-day/may-23-1949-federal-republic-of-germany-is-established

http://www.nationsonline.org/oneworld/History/Federal-Republic-Germany-history.htm