At the Potsdam Conference in 1945 the Allies agreed on the Soviet annexation pending the final determination of territorial questions at the peace settlement : The Conference has agreed in principle to the proposal of the Soviet Government concerning the ultimate transfer to the Soviet Union of the City of Koenigsberg and the area adjacent to it as described above subject to expert examination of the actual frontier . The U.S. President Harry Truman and the British Prime Minister Clement Attlee declared that they would support the proposal of the Conference at the forthcoming peace settlement
Potsdam Conference
Potsdam Conference
Kaliningrad