<Li> German Democratic Republic (GDR), commonly known as East Germany, was the smaller Marxist - Leninist socialist republic with its leadership dominated by the Soviet - aligned Socialist Unity Party of Germany (SED) in order to retain it within the Soviet sphere of influence . </Li> <P> After experiencing its Wirtschaftswunder or "economic miracle" in 1955, West Germany became the most prosperous economy in Europe . Under Chancellor Konrad Adenauer, West Germany built strong relationships with France, the United States, and Israel . West Germany also joined the North Atlantic Treaty Organization and the European Economic Community (later to become the European Union). East Germany stagnated as its economy was largely organized to meet the needs of the Soviet Union; the secret police (Stasi) tightly controlled daily life, and the Berlin Wall (1961) ended the steady flow of refugees to the west . Germany was reunited in 1990, following the decline and fall of the SED as the ruling party of the GDR . </P> <P> At the Potsdam Conference (17 July to 2 August 1945), after Germany's unconditional surrender on 8 May 1945, the Allies divided Germany into four military occupation zones--France in the southwest, Britain in the northwest, the United States in the south, and the Soviet Union in the east, bounded eastwards by the Oder - Neisse line . At Potsdam these four zones in total were denoted as' Germany as a whole', and the four Allied Powers exercised the sovereign authority they now claimed within Germany in agreeing' in principle' the future transfer of lands of the former German Reich east of' Germany as a whole' to Poland and the Soviet Union . These eastern areas were notionally placed under Polish and Soviet administration pending a final peace treaty (which was not formalized until 1990, 45 years later); but in actuality were promptly reorganized as organic parts of their respective sovereign states . </P> <P> In addition, under the Allies' Berlin Declaration (1945), the territory of the extinguished German Reich was to be treated as the land area within its borders as of 31 December 1937 . All Nazi land expansion from 1938 to 1945 was hence treated as automatically invalid . Such expansion included the League of Nations administered City - State of Danzig (occupied by Nazi Germany immediately following Germany's 1 September 1939 invasion of Poland), Austria, the occupied territory of Czechoslovakia, Suwalki, Alsace - Lorraine, Luxembourg, post 27 September 1939 "West Prussia", post 27 September 1939 "Posen Province", northern Slovenia, Eupen, Malmedy, the part of Southern Silesia ultimately detached from 1918 Germany by action of the Versailles Treaty, likewise, the Hultschiner Laendchen . </P>

When was germany divided into east and west