When the Second World War ended in 1945, Germany was divided into four zones of occupation which were governed by France, the Soviet Union, the United Kingdom and the United States.

 

Berlin was divided into four allied sectors.
 

 

 

 The three western zones were merged into the "Federal Republic of Germany", which was founded on May 23rd 1949.

 

The Soviet zone was given a constitution on October 7th 1949, hence it was known as "German Democratic Republic."

 

 

Unification of the two German states came into effect on October 3rd, 1990. 

images:

map of occupied zones: © Paasiviki: https://commons.wikimedia.org/wiki/File:Allied_occupation_in_Germany_(1945-1949).png

map of the two German states: © TUBES: https://commons.wikimedia.org/wiki/File:East-West-Germany-October_1949-July_1952.svg

map of unified Germany: https://en.wikipedia.org/wiki/File:Flag_map_of_Germany.svg