33rd Division 38th (Welsh) Division New Zealand Division When reformed for the Battle of Amiens: Cavalry Corps, commanded by Lieutenant-General Kavanagh 1st Cavalry Division 2nd Cavalry Division 3rd Cavalry Division III Corps, commanded by Lieutenant-General Richard Butler 12th (Eastern) Division 18th (Eastern) Division 47th (2nd London) Division, included the 131st Infantry Regiment, 33rd American Division 58th (2/1st London) Division Canadian Corps, commanded by Lieutenant-General Arthur Currie 32nd Division 1st Canadian Division 2nd Canadian Division 3rd Canadian Division 4th Canadian Division Australian Corps, commanded by Lieutenant-General John Monash 17th (Northern) Division 1st Australian Division 2nd Australian Division 3rd Australian Division 4th Australian Division 5th Australian Division. In September 1918 the Army was the only British force reinforced with substantial American (AEF) forces: II Corps, American Expeditionary Force under Major General George Read 27th Infantry Division AEF 30th Infantry Division AEF Commanders February 1916–February 1918 General Sir Henry Rawlinson February–March 1918 General Sir William Birdwood (temporary) April 1918–March 1919 General Sir Henry Rawlinson Second World War In the Second World War, no Fourth Army took the field but as part of the deception plans Operation Cockade and the later Operation Fortitude North, the Germans were encouraged to believe that a Fourth Army had been established with its headquarters in Edinburgh Castle and was preparing to invade Norway. The selection of the inactive Fourth Army was likely very deliberate because of its combat history during the First World War. That diverted and kept German units away from the real invasion zone in Normandy. In the subsequent Operation Fortitude South, the Fourth Army, with different units, was presented as part of the fictitious First United States Army Group (FUSAG) in its threat to the Pas-de-Calais. After Operation Market Garden, the Fourth Army was notionally intended to conduct Operation Trolleybar, an amphibious assault upon the coast of the Netherlands and later along the German coast. It was to involve a landing by the phantom 76th Infantry Division until the deception was ended in January 1945. Fictitious composition during Fortitude Fortitude North HQ at Edinburgh British II Corps (fictitious - HQ Stirling) 55th Infantry Division (Northern Ireland) 58th Infantry Division (fictitious, Aberlour) 113th Independent Infantry Brigade (garrison for Orkney and Shetland Islands) VII Corps (fictitious - HQ Dundee) 52nd (Lowland) Infantry Division (Dundee) US 55th Infantry Division (fictitious - Iceland) 7th, 9th & 10th US Ranger battalions (fictitious - Iceland) US XV Corps (Northern Ireland) US