Overview: The AIIied invasion of Europe on 6 June 1944 was the greatest all-arms combined operation in military history. Allied Supreme Commander, Dwight D Eisenhower, had an armada ol 6,000 ships, almost 1 million men, and a bewildering array of weapons and equipment for Operation Overlord. They faced a German enemy that was battle-hardened, formidable in defence, and commanded by one of the Wehrmacht's most experienced leaders, Gerd von Rundstedt. D-Day was a huge gamble, and its success or failure would decide the war in the West.