'Cobra' was the US break-out from the south-western edge of the 'Overlord' lodgement in Normandy in the Battle of St Lô (24/31 July 1944).
The operation was planned by Lieutenant General Omar N. Bradley’s US 1st Army of General Sir Bernard Montgomery’s Allied 21st Army Group, and its success transformed the high-intensity armour/infantry combat of Normandy into the high-speed mechanised eastward race across France. 'Cobra' therefore led directly to the creation of the 'Falaise pocket' and the loss of the German position in north-western France.
The original planning for the Normandy campaign, once 'Overlord' had been launched successfully, envisaged a rapid Allied build-up of forces in a lodgement which would be expanded steadily and took specific objectives such as towns, ports and airfields served on pre-determined dates.
The next stage of the Allied offensive was combat with the Germans in the type of mobile battle in which their advantages in numbers, tactical air strength, armour, mechanised infantry and logistics would prove decisive, and the Allies would thus be spared the type of stationary or, at best, slow-moving offensive which had typified World War I and led to horrendous casualties. A critical element of the Allied plans, after the success of the Normandy landing, was therefore the increase of their mechanised strength at a rate which the Germans could not match, and to this extent the Battle of Normandy was a race to create adequate forces more quickly than the enemy. The Allies thus had to build up their own forces as rapidly as possible, and at the same time hinder the Germans from achieving a comparable result.
To prevent additional German forces from entering the battle area, the Allied tactical air forces attempted to isolate the rail and road network of northern France. This effort was extremely successful, and as a result the German formations in Normandy suffered from severe personnel and supply shortages, and newly arrived units could be fed into the battle only very slowly. So decisive was the strength of the Allies' tactical air power that any German road movement by day became in effect suicidal.
The other half of the equation, which was the build-up of the Allied forces in the Normandy lodgement, was also succeeding. Though the strength of the Allied forces was growing more rapidly than that of the Germans, by July this growth was limited by the geographical factor of the Allies' failure to enlarge their lodgement’s area in line with the pre-invasion plan, which had also scheduled the arrival of the fresh formations. The lodgement was thus becoming ever more crowded, the number of airfields in Allied hands was far fewer than planned, the D-Day objective of Caen had still not been taken, and there was as yet no major operating port in Allied hands.
In general, therefore, Allied progress could be measured in World War I rather than World War II terms. The battle for Normandy had in effect degraded into a series of small unit actions in which Allied infantry units, with massive artillery support, slowly ground their way into the German defences. In the period 2/14 July, for example, Major General Troy H. Middleton’s VIII Corps suffered more than 10,000 casualties in the course of an advance of only 12,000 yards (10975 m). By the start of 'Cobra' on 25 July, the Allies had reached just the D+5 line, which the pre-invasion schedule had earmarked, as evident from its designation, for attainment by 11 June. This led to frustration right through the Allied forces as infantry losses were high, major mechanised forces could not yet be usefully committed to the battle, and effective close air support was difficult because the fighting was at such close quarters. The result was that the Allied commanders could not bring their advantages to bear, and this in turn led to a renewed fear of another stalemate.
This highlighted what was now seen as a significant failure in the planning of 'Overlord': so tight had been the focus on the problems of the invasion itself that there had been inadequate consideration of the campaign which would start after the lodgement had been secured. Moreover, on the 1st Army’s front on the western side of the Allied lodgement, the tactical difficulties posed by the bocage (sunken roads whose tall banks were topped by thick hedges) typical of this part of France had not been fully considered.
At the tactical level, the German defensive efforts were generally successful: their formations gave ground only slowly, and in the process inflicted heavy losses on the Allied forces, especially where the defence was aided by the bocage terrain.
In the more open terrain in the east, the German line was held by high-quality mechanised formations 1. In the west, facing the 1st Army, the Germans deployed only a few mechanised units 2, leaving most of their front to be held by infantry divisions which were effectively static.
At the strategic level, the Germans were playing a game they knew they would almost certainly lose: by 1944 nearly every combatant’s operational thinking was based on the concept that defensive lines should be held by infantry divisions, with mechanised formations behind them for counterattack. But the failure of German logistics to deliver sufficient infantry divisions to the front compelled the Germans to use and increasingly to expend their mechanised formations in a defensive battle of attrition.
Moreover, the complete inability of the German air force to contest air superiority with the Allies meant that the German ground formations could not conduct the sort of highly mobile combat in which they had so often proved themselves to be superb.
Finally, the astonishing willingness of the German high command to believe in the 'Fortitude' deception plan kept substantial German formations well to the east of the Normandy lodgement in the area of Generaloberst Hans von Salmuth’s 15th Army flanking SS-Obergruppenführer und General der Waffen-SS Paul Hausser’s 7th Army.
In an effort to break the near-stalemate in Normandy, Bradley began work on a breakthrough plan, and for some weeks worked virtually alone on the concept before revealing his plans on 10 July to Montgomery, his immediate superior, and to his British counterpart, Lieutenant General Sir Miles Dempsey commanding the 2nd Army. Montgomery and Dempsey agreed to supply the supporting attacks for the US operation. As they proceeded, though, Montgomery and Dempsey planned 'Goodwood' (i) as an Anglo-Canadian break-out before that of the Americans, and General Dwight D. Eisenhower, the Supreme Allied Commander in Europe, ensured that the Allied air forces would support the attack with tactical forces as well as medium and heavy bomber units.
The air commanders were reluctant to use their bombers in the tactical battle, believing that the aircraft and crews were unsuited to the role, and that they would therefore be better employed in their intended strategic role. Nevertheless, they participated in several 'carpet bombing' operations in Normandy on 7 July in 'Charnwood', on 18 July in 'Goodwood' (i), and on 24/25 July in 'Cobra'.
Bradley’s planning was designed to exploit the current German preoccupation with combating the British and Canadian activity around the city of Caen, and immediately drive a large gap through the German defences that were penning the 1st Army while the Germans were still distracted and militarily unbalanced. Once this gap had been widened and deepened into a corridor, the 1st Army would then be able to advance first to the south and then to the west into Brittany, rolling up the German flanks and freeing itself of the constraints imposed by operations in the bocage country of Normandy, and freeing Lieutenant General George S. Patton’s new US 3rd Army to move past the 1st Army left flank and drive at high speed to the south-east and then to the east in an offensive toward Paris and the Seine river.
After a slow start, 'Cobra' gathered momentum and German resistance collapsed as scattered remnants of broken units fought to escape either to the south-west into southern Brittany or to the east toward the Seine river. Lacking the resources to cope with the situation, the German response was ineffectual, and the entire Normandy front soon collapsed. Together with concurrent offensives by Dempsey’s British 2nd Army and, from 23 July, Lieutenant General H. D. G. Crerar’s Canadian 1st Army, was decisive in securing Allied strategic victory in the Normandy campaign.
Delayed several times by poor weather, 'Cobra' finally began on 25 July with a concentrated carpet bombing by thousands of Allied aircraft. Supporting offensives had drawn the bulk of German armoured reserves away to the east, toward the British and Canadian sector, and in combination with their shortage of men and matériel, this made it impossible for the Germans to create the successive lines of defence that would have been their only opportunity to halt the Allied break-out.
It was elements of Major General J. Lawton Collins’s US VII Corps which spearheaded the initial two-division assault while the 1st Army’s other two corps (Middleton’s VIII Corps on the right and Major General Charles H. Corlett’s XIX Corps on the left) delivered supporting attacks designed to pin the German formations opposite them. While the US advance was slow on the first day, but soon accelerated as the German opposition started to crumble once their thin defensive crust had been broken. By 27 July, most organised resistance had been overcome, and the VII and VIII Corps were advancing rapidly.
In 'Cobra' the three corps of the 1st Army totalled three armoured divisions and eight infantry divisions 3.
By 31 July the XIX Corps had destroyed the last forces opposing the 1st Army, and Bradley’s divisions were finally freed from the constraints of the bocage country. German reinforcements were moved to the west by Generalfeldmarschall Günther von Kluge, the Oberbefehlshaber 'West' and commander-in-chief of Heeresgruppe 'B', and employed in various counterattacks, of which the largest was 'Lüttich' conceived by Adolf Hitler and launched on 7 August between Mortain and Avranches. Although this led to the bloodiest phase of the battle, it involved formations which were already exhausted and well below strength, and had little effect other than a further degradation of von Kluge’s strength. On 8 August, troops of the new US 3rd Army captured Le Mans, formerly the headquarters of General Heinrich Eberbach’s 7th Army holding north-western France, and by this time 'Cobra' had transformed the Allies' campaign in this theatre into a campaign of rapid manoeuvre, paved the way to the creation of the Falaise pocket, and destroyed the German position in north-western France.
The situation which led to 'Cobra' was a direct consequence of events in the Normandy lodgement following the launch of 'Overlord' on 6 June. The Allied plan had called for progress inland to be made rapidly, but this had not happened anywhere along the front and, most especially, in its eastern sector. In order to facilitate the development of the Allied strength in Normandy and secure further expansion, the deep-water port of Cherbourg in the US sector to the west and the city of Caen in the British and Canadian sector to the east were early objectives. Thus the original plan called for powerful offensive efforts in both sectors, in which Dempsey’s British 2nd Army would secure Caen and the area to the south of it, and Bradley’s 1st Army would drive toward the line of the Loire river.
Montgomery had intended that Caen be taken on D-Day by British forces, with Cherbourg to be taken 15 days later by US forces. The 2nd Army was to seize Caen and then form a front to the south-east, extending to Caumont l’Eventé, to acquire airfields, and to protect the right flank of the 1st Army as this latter moved on Cherbourg. Possession of Caen and the area round it, desirable for the open terrain that would allow manoeuvre warfare, would also provide the 2nd Army with the area from which it could advance to the south and take Falaise, which could then be used as the pivot for a wheel slightly to the left and a further advance to Argentan and then toward the Touques river. The capture of Caen was possibly the single most important D-Day objective and was assigned to Lieutenant General J. T. Crocker’s British I Corps, but the task was too ambitious as the Caen sector contained the strongest German defences in Normandy.
The I Corps' first attempt to reach Caen on D-Day was blocked by elements of Generalleutnant Edgar Feuchtinger’s 21st Panzerdivision, and as the Germans then committed to the retention of the city most of the reinforcements sent to meet the invasion 4, the Anglo-Canadian front rapidly stagnated in the area to the north of Caen. 'Perch' (7/14 June) and 'Epsom' (26/30 June) resulted in some territorial gains and depleted the German strength, but Caen remained in German hands until 'Charnwood' (7/9 July), when the 2nd Army managed to take the north-western part of the city as far as the line of the Orne river.
The succession of Anglo-Canadian offensives around Caen had the effect, among other things, of persuading the Germans to commit the best of their reserves, including most of the available armour, against the eastern sector of the Allied lodgement. Despite this fact, the 1st Army was finding it very difficult to make progress against determined German resistance in the western sector of the lodgement. The slow pace of the US progress was also a reflection of the terrain in which the 1st Army was fighting, for its formations had neither training not experience in the type of combat dictated by the bocage terrain. Further difficulty was added to the Allied cause by the fact that the Allies had no major port facilities, which meant that the arrival of reinforcements and supplies had to be effected over the beaches via the two 'Mulberry' harbours and was therefore greatly vulnerable to weather conditions. In this latter capacity, on 19 June a severe three-day storm swept over the English Channel and caused major delays to the Allied build-up and also to the cancellation of some operations which had been planned.
Bradley eventually halted the 1st Army’s attempt to press to the south in the western sector just to the north of St Lô so that greater priority could be allocated to operations for the seizure of Cherbourg. The German defence of this port, which the Germans had believed to face only an attack from the sea, had not been organised well against a landward attack, and its main strength comprised four Kampfgruppen created out of the remnants of units which had retreated up the Cotentin peninsula. Even so, German organised resistance ended only on 27 June, when Major General Manton S. Eddy’s US 9th Division managed to reduce the defences of Cap de la Hague to the north-west of Cherbourg. Within four days, Collins’s VII Corps resumed the offensive toward St Lô alongside the VIII and XIX Corps, and this led to the movement of more German armour into the US sector.
The origins of 'Cobra' remain a matter for dispute. According to some British sources, the 'Cobra' concept came into being on 13 June, and the planning of the operation was greatly aided by the availability of 'Ultra' intelligence providing timely decrypts of communications between the German high command and the German military leadership in France. Montgomery’s plan at that time called for the 1st Army to take St Lô and Coutances and then make two thrusts to the south: one from Caumont toward Vire and Mortain, and the other from St Lô toward Villedieu and Avranches. Although pressure was to be kept up along the Cotentin peninsula towards La Haye du Puits near the peninsula’s western coast and Valognes in its centre, the capture of Cherbourg was not an immediate priority. With the VII Corps' capture of Cherbourg on 27 June, however, Montgomery’s initial timetable was rendered obsolete and the concept of a southward drive from Caumont was dropped.
After the end of 'Charnwood' and the cancellation of the 1st Army’s offensive toward St Lô, Montgomery met with his two army commanders, Dempsey and Bradley, on 10 July to discuss the 21st Army Group’s next step. At this meeting Bradley admitted that progress on the western flank was very slow. But Bradley had been working on plans for a break-out, codenamed 'Cobra', to be made by the 1st Army from 18 July. Bradley presented his idea to Montgomery, who approved it, and the directive which followed made it clear that the overall Allied strategy in the immediate future would be to draw German attention away from the 1st Army in the western sector to the 2nd Army in the eastern sector. Dempsey was ordered to 'go on hitting: drawing the German strength, especially the armour, onto yourself, so as to ease the way for Brad[ley]'. It was to implement this demand that 'Goodwood' (i) was planned and fought, and Eisenhower ensured that both operations would have the support of the heavy bombers of the Allied air forces.
On 12 July, Bradley briefed his 1st Army subordinate commanders about the operation, which was to be undertaken in three phases. The main effort would be under the control of Collins’s very powerful VII Corps. In the first phase, the breakthrough attack would be conducted by Eddy’s 9th Division and Major General Leland S. Hobbs’s 30th Division, which were to drive a hole in the German tactical zone and then hold the flanks of this penetration while Major General Clarence R. Huebner’s 1st Division and Major General Edward H. Brooks’s 2nd Armored Division pushed into the depth of the position until the German resistance collapsed. The 1st Infantry Division 'was to take Marigny, with this objective exploited by a stream of [Major General Leroy H.] Watson’s 3rd Armored Division armor that would move south toward Coutances'. The 2nd Armored Division, which was a component of Collins’s 'exploitation force' (the 2nd Armored Division in the east of the VII Corps' sector and the 1st Division reinforced by Combat Command B of the 3rd Armored Division in the west) was to 'pass through the 30th Division sector…and guard the overall American left flank'. If the VII Corps' effort was successful, the Germans' western position would become untenable, permitting a relatively easy US advance to the south-west end of the bocage country to cut off and seize the Brittany peninsula. The 1st Army’s intelligence branch estimated that no German counterattack would occur in the days immediately following the start of 'Cobra', and that if attacks materialised after that date they would be undertaken by units of no greater than battalion size.
Collins suggested a small number of slight modifications, aiming the breakthrough formations slightly farther to the south in the hope that, should the breakthrough be successful, his modification would open the way to a faster exploitation into Brittany for the seizure of the ports in that large peninsula. The original plan did not envisage the wholesale collapse of the German front in Normandy, but rather a major expansion of the lodgement, a transition to more mobile form of warfare beyond the bocage area, and the possible seizure of major ports.
Because the air attack was so critical a component of the plan, and the aircrew were dependent on good weather to locate and hit the right target, Air Chief Marshal Sir Trafford Leigh-Mallory, the Allies' air commander-in-chief for 'Overlord', was allocated the responsibility of setting the time of the attack.
Unlike previous US broad-front undertakings, the 'Cobra' assault was to be concentrated along a narrow front of only 7,000 yards (6400 m), and was to have very substantial air support. Fighter-bombers were to concentrate their efforts on hitting the German forward defences in a 250-yard (230-m) belt immediately to the south of the road linking St Lô and Periers, while the heavy bombers of Lieutenant General Carl A. Spaatz’s US Strategic Air Forces in Europe were to bomb to a depth of 2,500 yards (2285 m) behind the German main line of resistance. It was anticipated that the physical destruction and shock value of a short but very intense preliminary bombardment would greatly weaken the physical capability and psychological resilience of the the German defence, so in addition to the divisional artillery, corps- and army-level artillery elements would provide support: this included nine heavy, five medium and seven light artillery battalions. Thus something more than 1,000 pieces of divisional and corps artillery were committed to the offensive, and some 140,000 artillery rounds were allocated to the operation in just the VII Corps' sector, with another 27,000 for the VIII Corps' sector.
Furthermore, in an effort to overcome the mobility constraints imposed by the bocage, which had made offensive operations so difficult and costly for each sides, the 'Rhino' modification was effected on numbers of M4 Sherman medium and M5A1 Stuart light tanks, and as well as M10 tank destroyers, by fitting them with hedge-breaching 'tusks' able to force a path through the Norman hedgerows. While the German armour remained restricted to the roads, therefore, the US armour would now be able to manoeuvre more freely, although in practice these devices were not as effective as had been hoped. By the eve of 'Cobra', some 60% of the 1st Army’s tanks had been so equipped and, to preserve operational security, Bradley forbade their use until the start of 'Cobra', for which 1,269 M4 medium tanks, 694 M5A1 light tanks, and 288 M10 tank destroyers were available.
The German defence was provided by the two corps of Hausser’s 7th Army. These were General Eugen Meindl’s II Fallschirmkorps in the east and General Dietrich von Choltitz’s LXXXIV Corps in the west. Other German formations which arrived soon after the start of 'Cobra' included Generalleutnant Heinrich Freiherr von Lüttwitz’s 2nd Panzerdivision and Generalleutnant Gerhard Graf von Schwerin’s 116th Panzerdivision 5.
To the east of Caen, on 18 July, the British forces of Lieutenant General Sir Richard O’Connor’s VIII Corps and Crocker’s I Corps began 'Goodwood' (i), which started with the war’s greatest air bombardment in support of ground forces up to that time as more than 1,000 aircraft drop 5,350 tons of HE and fragmentation bombs from low altitude. The German positions to the east of Caen were shelled by 400 pieces of artillery, and a number of villages were reduced to rubble. Located farther to the south, on the Bourguébus ridge, the German artillery was outside the range of the British artillery, and the defenders of Cagny and Emiéville were largely unscathed by the bombardment. This contributed importantly to the losses suffered by the 2nd Army, which sustained more than 4,800 casualties. In what was largely an armoured offensive, the British lost between 250 and 400 tanks put out of action, although recent examination suggests that only 140 were completely destroyed and another 174 damaged. The operation resulted in the expansion of the Orne river bridgehead and the final capture of Caen.
Simultaneously, on the western flank of 'Goodwood' (i), the forces of Lieutenant General G. G. Simonds’s Canadian II Corps launched 'Atlantic' to strengthen the Allied foothold along the banks of the Orne river and to take the Verrières ridge to the south of Caen. 'Atlantic' made initial gains but lost momentum as the Canadian losses increased. Having cost the Canadians 1,349 men and with the heavily defended ridge firmly in German hands, 'Atlantic' was terminated on 20 July. However, at Montgomery’s urging prompted by strong words from Eisenhower, Simonds launched the Canadian II Corps into a second offensive a few days later. This 'Spring' had the limited but important aim of pinning German units and formations which might otherwise be transferred westward to the US sector, although Simonds took the opportunity to make another bid for Verrières ridge. Again the fighting for this ridge proved extremely bloody for the Canadians, and a counterattack by two German divisions pushed the Canadians back past their start lines and Simonds had to commit reinforcements to stabilise his front. In conjunction with 'Goodwood' (i), however, the Canadian operations caused the Germans to commit most of their armour and additional reinforcements to the British and Canadian sector, and 'Spring' had drawn SS-Brigadeführer und Generalmajor der Waffen-SS Sylvester Stadler’s 9th SS Panzerdivision 'Hohenstaufen' away from the US sector just before 'Cobra' was launched.
Thus it was just two Panzer divisions, with 190 tanks, which now faced the 1st Army, while seven Panzer divisions with 750 tanks (as well as all the PzKpfw VI Tiger heavy tank battalions and all three Nebelwerfer rocket-launcher brigades) were positioned in the area of Caen and therefore well to the east of the point at which 'Cobra' would be launched.
To gain good ground for the start of 'Cobra', Bradley and Collins conceived a plan to push forward to the road linking St Lô and Periers, along which the VII and VIII Corps were securing jumping-off positions. On 18 July, at a cost of 5,000 casualties, Gerhardt’s 29th Division and Baade’s 35th Division of Corlett’s XIX Corps took the vital heights of St Lô, driving back the defending elements of Meindl’s II Fallschirmkorps. The German paratroopers, together with Kraiss’s 352nd Division, which had been in action since its D-Day defence of Omaha Beach, were now in ruins, and the stage was fully set for 'Cobra'.
At this stage adverse weather, which also hampered 'Goodwood' (i) and 'Atlantic', persuaded Bradley to postpone 'Cobra' for a few days. This worried Montgomery as the British and Canadian operations had been launched to support a break-out attempt which was now not materialising. By 24 July the weather had improved sufficiently for Bradley to order the start of 'Cobra', and 1,600 Allied aircraft took off for Normandy. The air commanders had recommended a 3,000-yard (2750-m) distance between the rear edge of the bombing target area and the forward edge of any friendly forces. Because the cost of the limited attacks before 'Cobra' had been so high, however, Bradley was reluctant to give up too much of the hard-won ground and wanted to withdraw only 800 yards (730 m). In the end, the front-line infantry positions were withdrawn 1,200 to 1,400 yards (1100 to 1280 m) from the bombing zone to provide some measure of safety. Major formations moved back one hour before the start of the air attack, leaving observation posts behind until 20 minutes before H-hour. Poor weather on that day forced Leigh-Mallory to make another 24-hour postponement, but some heavy bombers of Lieutenant General James H. Doolittle’s US 8th AAF did not get the recall order and proceeded with their mission. About 335 Boeing B-17 Flying Fortress heavy bombers, some hindered in their bombing by poor visibility, dropped 685 tons of bombs, of which a proportion fell on US positions, despite the planning done to prevent just such an occurrence. This 'friendly fire' incident killed more than 25 Americans and wounded 130.
Some consideration was given to altering or cancelling the attack as it was a reasonable presumption that the element of surprise had been lost. But Bradley opted to proceed, and in fact the Germans did nothing to strengthen their defences in the 24 hours that now intervened before the attack on July 25. The Germans believed an attack had been attempted on 24 July, and that it had been checked by their artillery fire. Indeed, elements of the Panzer-Lehr-Division actually pulled back slightly to the south right into the bombers' target area. Elements of the 2nd Panzerdivision were pulled back toward the British sector in the east.
'Cobra' finally began fully at 09.38 on 25 July as some 600 Allied fighter-bombers attacked German strongpoints and artillery along a strip of ground, some 300 yards (275 m) wide, in the area of St Lô. For the next hour, 1,800 heavy bombers of Doolittle’s 8th AAF saturated an area 6,000 yards (5485 m) wide and 2,200 yards (2010 m) deep, on the road linking St Lô and Periers. Then it was the turn of a third wave of attackers as some 600 medium bombers soaked the same area with bombs.
Bradley had specifically requested that the aircraft approach the target area by flying parallel to the front in order to minimise the risk of friendly fire incidents. Although he believed the air commanders had committed themselves to the parallel route, in fact only the tactical fighter-bombers of Lieutenant General Lewis H. Brereton’s 9th AAF approached their targets on a line parallel with the front. The bomber units had made no such agreement and therefore approached on a line perpendicular to the front line. The bomb drops which fell short thus landed on the units tasked with spearheading the assault. The weight of the bombs dropped was in the order of 3,300 tons. Some 111 US soldiers were killed and 490 more were wounded: the 30th Division’s 1/120th Infantry suffered 25 soldiers killed and 131 wounded. Perhaps the most notable soldier to die was Lieutenant General Lesley J. McNair, the Commander-in-Chief Army Ground Force, who was in the area on an inspection.
Several factors contributed to the bombing errors, these including the small size of the target and the fact that wind blew smoke from the bombs toward the US positions. Some bomber crews bombed into the smoke rather than clearly identifying their targets. However, the friendly fire casualties that resulted were probably lower than the casualties that would have resulted from German fire had the bombers not been used.
The assault units recovered rapidly from the bombing and, despite heavy casualties in some units, only one battalion had to be replaced. Every other designated unit attacked that morning and though some units were delayed, the attack had begun by 11.00. Several German units had been devastated by the hail of bombs. The Panzer-Lehr-Division had been rendered completely ineffective: large numbers of its tanks had been destroyed or rendered unserviceable, positions had been destroyed, and the surviving personnel had often been 'shell shocked' into incoherence. Command and control largely broke down and two-thirds of the division’s personnel were casualties.
As noted above, by 11.00 the infantry had started to move forward, advancing from crater to crater beyond the shattered earth which had been the German outpost line. Although no serious opposition had been anticipated, the remnants of the Panzer-Lehr-Division, totalling some 2,200 men and 45 armoured fighting vehicles, had regrouped and were prepared to meet the the advance of the US troops. To the west of the Panzer-Lehr-Division, Wilke’s 5th Fallschirmjägerdivision had escaped the bombing almost intact. The men of the VII Corps were therefore somewhat disheartened to be greeted by fierce fire from the German artillery which, the Americans had persuaded themselves, must inevitably have been destroyed by the bombing. Several US units found themselves entangled in fights against strongpoints held by a handful of German tanks, supporting infantry and 88-mm (3.465-in) dual-role anti-aircraft and anti-tank guns, and the VII Corps advanced only 2,200 yards (2010 m) during the rest of the day.
Even if the results of the first day’s fighting were disappointing, Collins nonetheless found cause for encouragement in the fact that although the Germans were holding their positions with determination, these positions appeared not to constitute anything like a continuous line, and were therefore susceptible to being outflanked or bypassed. Even with prior warning of the US offensive, the Germans had become convinced by the British and Canadian actions around Caen that the real threat to their position in Normandy lay there, and tied down their available forces to such an extent that a succession of meticulously prepared defensive positions in depth, as encountered by the British and Canadians in 'Goodwood' (i) and 'Atlantic', had not been created to meet 'Cobra'.
During the morning of 26 July, Brooks’s 2nd Armored Division and Huebner’s 1st Division joined the attack as planned, reaching one of the first objectives for 'Cobra', namely a road junction to the north of Le Mesnil Herman, on the following day. Also on 26 July, Middleton’s VIII Corps entered the battle, led by Major General Donald A. Stroh’s 8th Division and Major General Eugene M. Landrum’s 90th Division. Despite the fact that they had clear axes of advance through the floods and swamps across their front, both divisions initially failed to make significant ground, but the break of day on the following day revealed that the crumbling of their left flank had compelled the Germans to fall back, leaving only large minefields to delay the VIII Corps' advance. By 12.00 on 27 July, the VII Corps' 9th Division was also past any organised German resistance and advancing rapidly.
By 28 July, the German defences across the US front had largely collapsed under the full weight of the advances of the VII and VIII Corps, and what resistance still survived was both patchy and disorganised. Watson’s 4th Armored Division of the VII Corps, which was entering combat for the first time, captured Coutances but met stiff opposition to the east of the town, and US units penetrating into the depth of the German positions were counterattacked at various places by elements of the 2nd SS Panzerdivision, 17th SS Panzergrenadierdivision and 353rd Division, which were all trying to scape encirclement. Brooks’s 2nd Armored Division was counterattacked with what was little short of desperation by German remnants, but this was a disaster and the Germans then abandoned their vehicles and fled on foot. Exhausted and demoralised, von Gross-Zauche und Camminetz reported that his Panzer-Lehr-Division had been destroyed, with its armour lost, its personnel either casualties or missing, and its headquarters records lost.
von Kluge was meanwhile gathering reinforcements, and elements of von Luttwitz’s 2nd Panzerdivision and von Schwerin’s 116th Panzerdivision were nearing the battlefield.
Corlett’s XIX Corps entered the fray on 28 July on the left of VII Corps, and between 28 and 31 July became embroiled with these reinforcements in the fiercest fighting since the start of 'Cobra'. During the night of 29 July, near St Denis le Gast to the east of Coutances, elements of the 2nd Armored Division found themselves fighting for their lives against a column of Tychsen’s 2nd SS Panzerdivision and Baum’s 17th SS Panzergrenadierdivision, which passed through the US line in the dark. Other elements of the 2nd Armored Division came under attack near Cambry and fought for six hours.
Bradley and his commanders knew that they were currently dominating the battlefield, however, and that desperate assaults of this nature were no threat to the overall US position. When ordered to concentrate his division, Oberst Heinz Günther Guderian, the senior staff officer of the 116th Panzerdivision, was frustrated by the very effective activities of Allied fighter-bombers: without the promised direct support of the 2nd Panzerdivision, Guderian stated, his Panzergrenadiers had no hope of delivering any effective counterattack on the Americans.
On 30 July, to protect the US operation’s flank and prevent the disengagement and redeployment of further German forces, the British VIII Corps and XXX Corps launched 'Bluecoat' southward from Caumont toward Vire and Mont Pinçon.
Advancing to the south along the west coast of the Cotentin peninsula later in the same day, the US VIII Corps seized Avranches, and by 31 July the XIX Corps had thrown back the last German counterattacks after fierce fighting, inflicting heavy losses in men and tanks. The US advance was now relentless, and the 1st Army had finally fought its way free of the constraints of the bocage country.
At 12.00 on 1 August, the US 3rd Army was activated under Patton’s command, Lieutenant General Courtney H. Hodges assumed command of the 1st Army and Bradley was promoted to the overall command of both armies, which constituted the US 12th Army Group. The US advance which followed was rapid in the extreme: between 1 and 4 August, the VIII Corps, now part of Patton’s 3rd Army, had swept through Avranches and over the bridge at Pontaubault to fan out into Brittany.
On 4 August Montgomery ordered a major change from the plan laid down before the start of 'Overlord': given the German collapse on the south-western corner of the Cotentin peninsula, the primary task of the 3rd Army was switched from a westward sweep into Brittany in an effort to open the region’s ports, to a south-eastward sweep by Major General Wade H. Haislip’s XV Corps and Major General Walton H. Walker’s XX Corps in an effort to trap several German armies in combination with an Anglo-Canadian advance south-east from a point east of Caen. Thus began the race to create and then to close the 'Falaise pocket', and finally to launch the Allied dash across France.
The German forces in Normandy had by now been so severely hammered by Allied offensives that, without even the prospect of major reinforcement in the wake of the Soviet forces' huge 'Bagration' summer offensive against Generalfeldmarschall Walter Model’s (from 17 August Generaloberst Georg-Hans Reinhardt’s) Heeresgruppe 'Mitte' on the Eastern Front, very few Germans believed that defeat could be avoided. Even so, rather than order his remaining forces to withdraw to the line of the Seine river, Hitler directed von Kluge to make an 'immediate counterattack between Mortain and Avranches' to annihilate the Americans and penetrate to the west coast of the Cotentin peninsula. Eight of the nine Panzer divisions in Normandy were to have been used in the attack as it was conceived by Hitler, but the exigencies of the German position in Normandy meant that only four of these (one of them incomplete) could be withdrawn from their defensive tasks and assembled in time for the offensive. The German commanders on the spot immediately protested that such an operation was impossible given their very limited remaining resources, but Hitler overruled these objections and the 'Lüttich' counter-offensive was launched on 7 August in the area around Mortain. The 2nd Panzerdivision, 1st SS Panzerdivision and 2nd SS Panzerdivision led the assault, although with only 75 PzKpfw IV battle tanks, 70 PzKpfw V Panther battle tanks and 32 self-propelled guns between them. Wildly ambitious but militarily ridiculous, the German offensive was over within 24 hours, although fighting continued until 13 August.
With von Kluge’s few remaining combat-effective formations destroyed by the US 1st Army and British 8th Army, the Allied commanders realised that the entire German position in Normandy was collapsing. On 14 August, in conjunction with US movements north toward Chambois, Canadian forces launched 'Tractable' to the south, the Allied intention being to trap and destroy the whole of Hausser’s 7th Army and SS-Oberstgruppenführer und Generaloberst der Waffen-SS Josef Dietrich’s 5th Panzerarmee near the town of Falaise. Five days later, the two arms of the Allied encirclement were almost complete as Landrum’s US 90th Division had made contact with Major General Stanisław Maczek’s Polish 1st Armoured Division, and the first Allied units crossed the Seine river at Mantes Gassicourt even while German units were still retreating or fleeing to the east by any means they could find.
By 22 August, the Falaise pocket, which the Germans had been fighting desperately to keep open to allow their trapped forces to escape, was finally closed, effectively ending the Battle of Normandy with a decisive Allied victory: the German losses amounted to more than 400,000 men as well as 1,500 tanks and self-propelled guns, and some 25 divisions were essentially destroyed.. All of the German forces to the west of the Allied lines were now dead or in captivity, and although perhaps 100,000 Germans succeeded in escaping, they managed to do so only be abandoning 40,000 to 50,000 prisoners and more than 10,000 dead; 344 tanks and self-propelled guns, 2,447 soft-skinned vehicles and 252 pieces of artillery pieces in the northern part of the pocket alone.
The German losses during the Allied break-out from the Normandy lodgement were much higher than those of the more static battles that preceded it: the loss rate of German tanks accelerated in August by comparison with those of June or July, and as a result the surviving Panzer divisions arrived on the German frontier exhausted and without tanks.
The Allies were able to advance freely through undefended territory, and by 25 August all four Allied armies (Canadian 1st, British 2nd and US 1st and 3rd) had reached the line of the Seine river. The sense of impending stalemate which had become evident in the Allied high command by the middle of July had by now been replaced by the euphoria of victory. To some extent both sides believed the war was as good as over. The Allies followed up the dash across France with the short-sighted decisions to forego the clearing of the approaches to the great port of Antwerp in favour of the tempting but ultimately fruitless 'Market' and 'Garden' operations at Arnhem.
From west to east, the LXXXIV Corps comprised Generalmajor Bernard Klosterkemper’s 243rd Division, Generalleutnant Eugen König’s Gruppe 'König' (remnants of König’s own 91st Division, Oberst Rudolf Bacherer’s 77th Division and a Kampfgruppe of Generalleutnant Walter Düvert’s 265th Division), SS-Standartenführer Christian Tychsen’s 2nd SS Panzerdivision 'Das Reich', SS-Brigadeführer und Generalmajor der Waffen-SS Otto Baum’s 17th SS Panzergrenadierdivision 'Götz von Berlichingen', Generalleutnant Gustav Wilke’s 5th Fallschirmjägerdivision and Bayerlein’s Panzer-Lehr-Division, with Generalleutnant Erich Müller’s 353rd Division in corps reserve and Generalleutnant Hans Schmidt’s 275th Division in 7th Army reserve.