June 6, 1944, the beginning of the end. With Dwight D. Eisenhower as the Supreme Commander of all Allied military, "Operation Overlord" was a complete success as the German armies were pushed off the beaches of Normandy and forced to retreat all the way across the Rhine and back to Germany. The European theater of World War II was coming to an end and would officially end with the total surrender of Germany in the spring of 1945, less than one year after D-Day invasion. What was involved in the planning, who was to be involved, and when would the planned Operation Overlord (D-Day) invasion actually occur? There were so many contingencies to be considered with weather being one of them.