Stalin, Truman and Churchill. July 1945 The Potsdam Conference, which began on July 17, 1945, was the last meeting of the "Big Three" - leaders of the USSR, the USA and England, the main powers of the anti -Hitler coalition. Harry Truman, who died on April 12, 1945, was replaced by Harry Truman, and the loser of the parliamentary elections, British Prime Minister Winston Churchill left Potsdam at the end of July - he was replaced by Labor leader Clemens Ettley.