 The deception plan aimed to keep the German garrison of nearly half a million men stationed in Norway to resist such an attack.Following the invasion of Normandy, the Fourth Army was "transferred" south to reinforce the First United States Army Group (FUSAG), another fictitious formation.Fortitude South aimed to convince the Germans that FUSAG had 500,000 men in more than fifty divisions and would launch the main Allied invasion in the Pas de Calais, 45 days after the Normandy landings.