Supreme Commander, Allied Expeditionary Force (SCAEF): This was Eisenhower's most famous and consequential title, which he held from late 1943 until the end of the war in Europe. In this capacity, he was the supreme commander of all Allied forces in the European Theater of Operations. He was responsible for planning and executing Operation Overlord, the Allied invasion of Normandy on D-Day, June 6, 1944, and the subsequent campaign to defeat Nazi Germany.