Less than one year after the invasion of Poland, Adolf Hitler and the armed forces of the Third Reich had decimated the Western Front, conquered France and drove 338,000 British Expeditionary Force and Allied troops from the beaches of Dunkirk and back to the British Isles. Following the loss, rudimentary plans began to to retake a French bridgehead, allowing Allied troops to combat the Nazi forces and free France.
By the summer of 1943, the war in Europe had been grinding on for almost four years, bringing about the deaths of millions of soldiers and civilians. Losses were especially heavy in the East, where Soviet soldiers continued to fight the encroaching German troops with alternating victories and defeats. After the German catastrophe at Stalingrad, with the killing of more than 250,000 German and Romanian solders, and 91,000 others taken prisoner, Allied leaders had decided that it was time to re-establish a two-front war and speed up the final destruction of the German war machine.
During the Tehran conference in 1943, Franklin Roosevelt, Winston Churchill and
