In April 1945 , Erfurt and Buchenwald were liberated by the US Army . It had already been agreed in the Yalta Conference , held in February 1945 , that the area would come under Soviet control after the Germans had been defeated . It was handed over on 3 July 1945 . In 1949 the Soviet Occupied Zone became the German Democratic Republic ( East Germany )
Yalta Conference
Yalta Conference
Topf and Sons