D-Day Deception: Operation Fortitude and the Normandy Invasion

Date of Award


Degree Type


Degree Name

Doctor of Philosophy (PhD)



First Advisor

Andrew Wiest

Advisor Department



On 6 June 1944 Allied forces stormed the beaches at Normandy. The invasion followed several years of argument and planning by Allied leaders, who remained committed to a return to the European continent after the Germans had forced Allied forces to evacuate at Dunkirk in May 1940. Before the spring of 1944, however, Prime Minister Winston Churchill and other British leaders remained unconvinced that the invasion was feasible. At the Teheran Conference in November 1943, President Franklin D. Roosevelt and Churchill promised Josef Stalin that Allied troops would launch Operation Overlord, the invasion of Normandy, in the spring. Because of their continuing concerns about Overlord, the British convinced the Americans to implement a cover plan to help insure the invasion's success. The London Controlling Section (LCS) devised an elaborate two-part plan called Operation Fortitude that SHAEF (Supreme Headquarters, Allied Expeditionary Force) helped to fine tune and that both British and American forces implemented. Allied forces, both real and imaginary, stationed in Scotland, Northern Ireland, and Iceland implemented Fortitude North, which created a threat to Norway. Other Allied formations situated in east and southeast England participated in Fortitude South, which suggested a threat to the French coast east of Normandy in an area called the Pas de Calais. SHAEF and the LCS hoped the Fortitude deception would accomplish several things. First, they wanted the threats to Norway and the Pas de Calais to convince the Germans to deploy their troops in regions outside of Normandy. Second, the deception planners, by maintaining the deception after the invasion, expected the Germans to conclude that Overlord was not the main Allied offensive and that it was a feint designed to draw German forces away from the real target, the Pas de Calais. Finally, SHAEF and the LCS hoped to prevent to prevent the German reinforcernent of Normandy by suggesting that the large Allied force remaining in southeast England would land in the Pas de Calais in mid-July. Historians analyzing the Normandy invasion frequently devote some discussion to Operation Fortitude. Although they admit that Fortitude North did not accomplish all that the Allied deception planners had hoped, many historians heap praise on Fortitude South, using phrases such as, "unquestionably the greatest deception in military history." Many of these historians assume that the Fortitude deception played a crucial role in the June 1944 Allied assault. This reexamination of the sources suggests, however, that other factors contributed as much, if not more, to the Allied victory in Normandy and that Allied forces could have succeeded without the elaborate deception created by the LCS.