The entirety of Germany was militarily occupied by the Allies from the Berlin Declaration on 5 June 1945 to the establishment of West Germany on 23 May 1949. After Nazi Germany (1933–1945) of the German Reich (1871–1945) surrendered to the Allies and collapsed on 8 May 1945, the four countries representing the Allies (United States, United Kingdom, Soviet Union, and France) asserted joint authority and sovereignty with the Allied Control Council (ACC) at the 1945 Berlin Declaration. At first, defining Allied-occupied Germany as all territories (1922–1938) of the former German Reich before the Nazi annexing of Austria and later at the 1945 Potsdam Conference of the Allies themselves, the Potsdam Agreement on 1 August decided the new eastern German border by giving Poland and the Soviet Union all regions of Germany east of the Oder–Neisse line (eastern parts of Pomerania, Neumark, Posen-West Prussia, East-Prussia & almost Silesia) and divided the remaining "Germany as a whole" into the four occupation zones for administrative purposes under the United States, the United Kingdom, France, and the Soviet Union. Although the three of Allies (United States, United Kingdom, and Soviet Union) agreed about the occupation, division, and border of Germany in the 1943 Tehran Conference in Iran before, the four occupied zones located in Germany were only agreed by the three Allies at the February 1945 Yalta Conference. All territories annexed by Germany before the war from Austria and Czechoslovakia were returned to these countries. The Memel Territory, annexed by Germany from Lithuania before the war, was annexed by the Soviet Union in 1945 and transferred to the Lithuanian SSR. All territories annexed by Germany during the war from Belgium, France, Italy, Luxembourg, Poland and Yugoslavia were returned to their respective countries. Deviating from the occupation zones planned according to the London Protocol in 1944, at Potsdam, the United States, United Kingdom and the Soviet Union approved the detachment from Germany of the territories east of the Oder–Neisse line, with the exact line of the boundary to be determined in a final German peace treaty. This treaty was expected to confirm the shifting westward of Poland's borders, as the United Kingdom and United States committed themselves to support the permanent incorporation of eastern Germany into Poland and the Soviet Union. From March 1945 to July 1945, these former eastern territories of Germany had been administered under Soviet military occupation authorities, but following the Potsdam