It was commanded by Generalfeldmarschall Gerd von Rundstedt at the time of Operation Overlord. Hitler's refusal to release the armored reserve until 1430 hours on D-day prevented the Germans from eliminating the allied beachheads while they were lightly held. Thus, the Westheer was embroiled in a battle of attrition which it could not win. Particularly difficult was the surrounding bocage of the Norman countryside, which seriously hampered armored operations and the allied bombing, which prevented the Germans from receiving reinforcements in strength. After Operation Cobra, the Westheer's order of battle was decimated by the destruction of the Falaise pocket, which consisted primarily of Army Group B.