move without talking to Broadhurst, and the two gradually became friends. Main HQ was presided over by Chilton. Chilton and Dempsey would meet every day, usually at Tac HQ. Chilton later became Deputy Adjutant General at 21st Army Group HQ, and he was replaced as chief of staff by Brigadier Harold "Pete" Pyman on 23 January 1945. Rear HQ was normally situated or so further back and contained the rest of Second Army HQ. It was presided over by the Quartermaster General, Brigadier Geoffrey Hardy-Roberts. In all, Second Army HQ had a strength of 189 officers and 970 other ranks. The Battle for Caen degenerated into a battle of attrition during which the Anglo-Canadian forces were frustrated by determined German resistance. This fighting drew vital German units including the bulk of their armoured strength to the Caen sector, which facilitated Operation Cobra, the breakout further west by Lieutenant General Omar Bradley's U.S. First Army. Dempsey convinced Montgomery to allow him to make an attempt at a breakthrough using three armoured divisions, assisted by heavy bombers dropping of bombs. This was Operation Goodwood. Launched on 18 July, it resulted in a costly advance. Goodwood increased the pressure on the German forces and inflicting heavy casualties on them. Montgomery succeeded in his principal aim of drawing away German reserves from Bradley's front, for by 25 July, when Operation Cobra commenced, the Germans had 600 tanks, including all the heavy battalions with Tiger I and Tiger II tanks, opposite the Second Army and just 100 facing the U.S. First Army. Dempsey argued after the war that Goodwood had succeeded in many of its strategic aims but there was no breakthrough. There were calls for Montgomery to be sacked, although this was never likely, but little criticism of Dempsey despite him being the architect and directly responsible for some of its tactical flaws. Dempsey's tactics were based on combat experience in the desert and Italy, but they were not always as applicable or as effective in Normandy. Doctrine called for armour and infantry to be employed in separate brigades, but in Normandy closer cooperation between the two was required. In the wake of Goodwood, the armoured divisions were reorganised, with infantry battalions and armoured regiments operating together in pairs. O'Connor had urged the adoption of armoured personnel carriers for the infantry, but Dempsey had not agreed to this. Dempsey's use of aerial bombardment and