 By 31 July, XIX Corps had destroyed the last forces opposing the First Army, and Bradley's troops were finally freed from the bocage. Reinforcements were moved west by Field Marshal Günther von Kluge and employed in various counterattacks, the largest of which (codenamed Operation Lüttich) was launched on 7 August between Mortain and Avranches. Although this led to the bloodiest phase of the battle, it was mounted by already exhausted and understrength units, and had little effect other than to further deplete von Kluge's forces. On 8 August, troops of the newly activated Third United States Army captured the city of Le Mans, formerly the German Seventh Army's headquarters. Operation Cobra transformed the high-intensity infantry combat of Normandy into rapid maneuver warfare, and led to the creation of the Falaise pocket and the loss of the German position in northwestern France.
