Question: During Operation Fortitude  what was the purpose of the deception?
About the article "Invasion of Normandy", section "Assessment of the battle".

Candidate passages:
Operation Fortitude was the code name for a World War II military deception employed by the Allied nations as part of an overall deception strategy (code named Bodyguard) during the build-up to the 1944 Normandy landings.
Fortitude was divided into two sub-plans, North and South, with the aim of misleading the German high command as to the location of the imminent invasion.
Both Fortitude plans involved the creation of fake field armies (based in Edinburgh and the south of England) which threatened Norway (Fortitude North) and Pas de Calais (Fortitude South).
The operation was intended to divert Axis attention away from Normandy and, after the invasion on June 6, 1944, to delay reinforcement by convincing the Germans that the landings were purely a diversionary attack. 
During the Second World War, Lieutenant Colonel Fleetwood-Hesketh was a member of Ops (B), the deception section of SHAEF that helped plan Operation Fortitude, a key portion of Operation Bodyguard, the deception plan covering the Allied invasion of Normandy in 1944.
He wrote a history of his role and the operation that was published after his death.
Following the end of the war, Hesketh was sent to Germany, alongside his brother, to search through the files of German intelligence, and question officers.
He was then asked to write a history of deception in Western Europe, including the work up to and including Operation Fortitude. 
Fortitude was one of the major elements of Operation Bodyguard, the overall Allied deception stratagem for the Normandy landings.
Bodyguard's principal objective was to ensure the Germans would not increase troop presence in Normandy by promoting the appearance that the Allied forces would attack in other locations.
After the invasion (on June 6, 1944) the plan was to delay movement of German reserves to the Normandy beachhead and prevent a potentially disastrous counter-attack.
Fortitude's objectives were to promote alternative targets of Norway and Calais.
The planning of Operation Fortitude came under the auspices of the London Controlling Section, a secret body set up to manage Allied deception strategy during the war.
However, the execution of each plan fell to the various theatre commanders, in the case of Fortitude this was Supreme Headquarters Allied Expeditionary Force (SHAEF) under General Dwight D. Eisenhower.
A special section, Ops (B), was established at SHAEF to handle the operation (and all of the theatre's deception warfare).
The LCS retained responsibility for what was called "Special Means"; the use of diplomatic channels and double-agents.
Fortitude was split into two parts, North and South, both with similar aims.
Fortitude North was intended to convince the German high command that the Allies, staging out of Scotland, would attempt an invasion of occupied Norway.
Fortitude South employed the same tactic, with the apparent objective being Pas de Calais. 
Operation Titanic was conducted as part of Operation Bodyguard, a broad strategic military deception intended to confuse the Axis high command as to Allied intentions during the lead-up to the Normandy landings.
The Allies had a number of deception plans in connection with the planned invasion of Europe.
Operation Fortitude was the deception operation for the Normandy landings or Operation Overlord.
It was divided into "Fortitude North", a threat to invade Norway, and "Fortitude South", designed to induce the Germans to believe that the main invasion of France would occur in the Pas de Calais rather than Normandy.
The Royal Air Force as part of Fortitude had their own deception missions.
Starting on 5 June there were four operations.
Two of them entailed the dropping of Window–strips of aluminum designed to give false radar readings–over the English Channel to simulate the approach of a large fleet.
These were Glimmer by No.
218 Squadron and Taxable by No.
617 Squadron.
The third was intended to jam the German radar, Airborne Cigar by No.
101 and No.
214 squadrons.
The final operation was Titanic. 
The most significant operation with which LCS was associated was Operation Fortitude, the cover and deception for the Normandy invasion in 1944.
The strategic plan for Allied deception in 1944, Operation Bodyguard, was drawn up by LCS, which set down the general story of Fortitude.
Fortitude was however implemented by the "Ops (B)" section of SHAEF, under General Eisenhower.
Ops (B) was composed of two sections, one dealing with physical deception and the other dealing with Special Means, that is, controlled leakage.
Initially, the TWIST Committee of the LCS selected the channels for dissemination of controlled leakage.
Ultimately, the TWIST committee was abolished and Ops (B) was allowed to deal directly with Section B1A of MI5, which managed controlled agents.