and based around the fictional British Fourth Army, based in Edinburgh. The Fourth Army had first been activated the previous year, as part of Cockade to threaten Norway and tie down the enemy divisions stationed there. The Allies created the illusion of the army via fake radio traffic (Operation Skye) and leaks through double agents. Fortitude South employed similar deception in the south of England, threatening an invasion at Pas-de-Calais by the fictional 1st U.S. Army Group (FUSAG) led by U.S. General George Patton. France was the crux of the Bodyguard plan: with Calais as the most logical choice for an invasion, the Allied high command had to mislead the German defences in a very small geographical area. The Pas-de-Calais offered advantages over the chosen invasion site, such as the shortest crossing of the English Channel and the quickest route into Germany. Having a high regard for Patton, German command, particularly Rommel, took steps to heavily fortify that area of coastline. The Allies decided to amplify this belief of a Calais landing. General Bernard Montgomery, commanding the Allied landing forces, knew that the crucial aspect of any invasion was the ability to grow a beachhead into a full front. He also had only limited divisions at his command, 37 compared to around 60 German formations. Fortitude South's main aims were to give the impression of a much larger invasion force (the FUSAG) in the South-East of England, to achieve tactical surprise in the Normandy landings and, once the invasion had occurred, to mislead the Germans into thinking it was a diversionary tactic with Calais the real objective. Operation Ironside While Fortitude represented the major thrust of Bodyguard in support of the Normandy landings, several smaller plans added to the overall picture of confusion. On the Western Front, the largest of them was Operation Ironside. Intercepted communications during January 1944 indicated German high command feared the possibility of landings along the Bay of Biscay, particularly near Bordeaux. The next month, it ordered anti-invasion exercises to be carried out in the region. To play on those fears, the Allies instigated Operation Ironside. The plot for Ironside was that two divisions sailing from the United Kingdom would land on the Garonne estuary ten days after D-Day. After a beachhead had been established, a further six divisions would arrive directly from the United States. The force would then capture Bordeaux before it linked up