Question: why was germany divided into east and west by 1949

title: History of Germany (1945–90)
text: On 28 November , West German Chancellor Helmut Kohl outlined the 10 - Point Plan for the peaceful unification of the two German states , based on free elections in East Germany and a unification of their two economies . In December , the East German Volkskammer eliminated the SED monopoly on power , and the entire Politbüro and Central Committee -- including Krenz -- resigned . The SED changed its name to the Party of Democratic Socialism ( PDS ) and the formation and growth of numerous political groups and parties marked the end of the communist system . Prime Minister Hans Modrow headed a caretaker government which shared power with the new , democratically oriented parties . On 7 December 1989 , an agreement was reached to hold free elections in May 1990 and rewrite the East German constitution . On 28 January , all the parties agreed to advance the elections to 18 March , primarily because of an erosion of state authority and because the East German exodus was continuing apace ; more than 117,000 left in January and February 1990 .