Original: East Berlin was officially called Berlin, Hauptstadt der DDR ("Berlin, Capital of the GDR"), or simply "Berlin," by East Germany, and "Berlin (Ost)" by the West German government, "Ost-Berlin", "Ostberlin" or "Ostsektor" by West German media.
Simplified: East Berlin was officially called Berlin, Hauptstadt der DDR ("Berlin, Capital of the GDR"), or simply "Berlin," by East Germany.