'Overlord' was the Allied invasion of Normandy in north-western France up to the time of the break-out and advance to the line of the Seine river (6 June/19 August 1944).

The Allies assigned a number of codenames to the various stages of the invasion: among these were 'Overlord' for the establishment of a large-scale and operationally viable lodgement on the continent, and 'Neptune' (iii) for the 'triphibious' first phase to gain and hold the secure initial foothold by means of air, land and sea forces. Thus 'Overlord' was the Allied invasion of North-West Europe, which was started by the 'Neptune' (iii) initial assault phase: 'Neptune' (iii) began on 6 June (D-Day) and ended on 30 June 1944, by which date the Allies had established a firm foothold in Normandy; and 'Overlord' proper also began on 6 June but continued until the Allied forces had crossed the Seine river on 19 August 1944.

Such an invasion had been long wished by the Allies, and although the bulk of the Allied forces were provided by the UK, USA and Canada, there were also contributions from Australia, Belgium, Czechoslovakia, France, Greece, Luxembourg, the Netherlands, New Zealand, Norway and Poland.

The final 'Overlord' plan was accepted in outline at the 'Trident' conference in Washington during 1943 only after the Allied planners had appreciated that any premature effort (such as 'Sledgehammer' in 1942 and 'Round-up' in 1943) stood little real chance of success against an enemy who maintained strong forces in France under an able leadership. The Allies therefore decided to bide their time (despite Soviet insistence that a 'second front' be opened against the Germans in the west as a means of easing pressure on the Eastern Front) until they had the right strength of adequately trained and equipped forces, supported by the necessary naval and air forces, to deliver a decisive stroke.

Rather than any repetition of the type of head-on frontal assault characteristic of Western Front operations in World War I, the British in general and Prime Minister Winston Churchill in particular favoured attacks on the periphery of German-occupied Europe and allowing the insurgency work of the Special Operations Executive to reach large-scale fruition, while making a main Allied thrust from the Mediterranean to Vienna in Austria and thence into Germany from the south. The British also believed that such an approach would provide the advantage of creating a barrier to limit the Soviet advance into Europe.

The USA, on the other hand, believed from the outset that the optimum approach was that characteristic of US military doctrine, namely the most direct (and therefore shortest) route straight into Germany from the strongest Allied power base. The Americans were adamant in their view that the direct approach was altogether superior to the indirect approach favoured by the British, and made it clear that this was the only option they would support in the long term.

The two preliminary proposals which were drawn up were 'Sledgehammer' for an invasion in 1942, and 'Round-up' for a larger attack in 1943. The latter was adopted and further developed into 'Overlord', although for implementation in 1944 rather than 1943. This decisive stroke was not to be merely the occupation of a substantial lodgement in German-occupied France, but the beginning of a major strategic drive through France and into Germany with the object of Germany’s total defeat.

Planning for 'Overlord' was undertaken by a number of teams under the control of SHAEF (Supreme Headquarters Allied Expeditionary Forces) but closely supervised by the Combined Chiefs-of-Staff Committee. Heading SHAEF was General Dwight D. Eisenhower, with Air Chief Marshal Sir Arthur Tedder as his deputy and Lieutenant General Walter Bedell Smith as his chief-of-staff. Command of the invasion forces was entrusted to General Sir Bernard Montgomery. There had been considerable pressure for a joint command of the Allied forces for 'Overlord', with Montgomery heading the Anglo-Canadian forces and Lieutenant General Omar N. Bradley the US forces, but Eisenhower insisted on a single commander for the unitary Allied 12^th Army Group which would launch the landing and undertake the break-out from the lodgement, though the arrival of more troops in France in the exploitation after the break-out would make necessary the formation of two army groups, namely Montgomery’s Anglo-Canadian 21^st Army Group and Bradley’s US 12^th Army Group, whereupon Eisenhower would assume command in France over both army group chiefs.

Allied strategic thinking had initially been centred upon a landing in the Pas de Calais region, which offered a relatively narrow water crossing and then good terrain for a rapid advance, but it was soon clear that this was just was the Germans were expecting, Generalfeldmarschall Gerd von Rundstedt (the Oberbefehlshaber 'West') and Generalfeldmarschall Erwin Rommel (commanding Heeresgruppe 'B') having disposed Generaloberst Hans von Salmuth’s powerful 15^th Army in this area with 14 first-line infantry divisions (plus another three refitting or forming) and five first-line Panzer divisions (plus another two refitting or forming). So Allied thoughts were switched to locations farther to the west, where the beaches of Normandy (between Le Havre in the east and Cherbourg in the west) offered adequate sites for the landing against Generaloberst Friedrich Dollmann’s 7^th Army with 14 first-line infantry divisions (including two parachute divisions and with another infantry division forming).

The short tactical radius of Allied fighters and fighter-bombers operating from airfields in southern England also greatly limited the choices of amphibious landing sites. Largely as a result of the lessons learned from the disastrous 'Jubilee' attack on Dieppe during August 1942, the Allies also decided not to assault a French port directly in the course of their first assault. Landings in force on a broad front in Normandy would permit simultaneous threats then to be developed to the north-west against the port of Cherbourg, to the south-west against the ports of Brittany, to the north-west against the port of Le Have, and also to the south-east toward Paris and the border of Germany. Normandy was a less well defended coast and an unexpected but nonetheless useful strategic jumping-off point, with the potential to confuse and scatter the German defending forces. Normandy was suitable for the tactics in which the Allied formations had been trained.

It is worth noting that the Allied formations to be used in 'Overlord' were well trained and well equipped but, for the most part, untried in battle.

The first real plan for the Normandy landings was known as the COSSAC plan, named for the Chief-of-Staff Supreme Allied Commander staff under Lieutenant General Sir Frederick Morgan. This plan was devised in late 1943, and immediately fell foul of Eisenhower and Montgomery. The US commander objected to the plan because it called for a narrow-front landing by a mere three divisions, with just two more divisions as floating reserve; failed to allow for a rapid build-up in the beach-head area; and made no provision for the capture of Cherbourg at the head of the Cotentin peninsula. Eisenhower was adamant that the early seizure of a major port was essential for the assured delivery of the follow-on forces and the supplies that were essential for the lodgement to be maintained against the powerful counter-offensive that must inevitably be launched once the Germans had established the real nature of the Allied effort. Montgomery objected to the COSSAC plan on the grounds that it was based on a landing which he believed to be too narrow, especially as by D+12 some 12 divisions were scheduled to come ashore over the same beaches, this figure increasing to 24 divisions by D+24. In these circumstances Montgomery anticipated that the beach areas would become huge traffic jams, throwing Allied operations completely out of gear and constituting ideal targets for German air (and missile) activity.

Montgomery went one step further than criticising the COSSAC plan and also suggested his ideal concept, in which a broad-front landing would be made only after the successful completion of an Allied air offensive to eliminate German air units in the area. Montgomery thus advocated that the British and US armies should each have their own group of landing beaches, each beach being used for a single corps (both assault divisions and follow-up divisions) and sufficiently separated from other beaches so that each corps would have freedom of tactical action in developing its beach-head before the entire army group moved rapidly to secure at least two major ports or groups of smaller ports, ideally one to each army.

Though his objections to the COSSAC plan were different to those of Montgomery, Eisenhower also saw his subordinate’s point of view, and modifications were worked into the basic COSSAC scheme to create the 'Overlord' plan whose objectives were by D+40 to create a lodgement including the cities of Caen and Cherbourg (the latter for its deep-water port), break out from this lodgement to liberate Brittany and take its Atlantic ports, and advance to a line about 125 miles (200 km) to the south-west of Paris and extending along a line from Le Havre on the estuary of the Seine river through Le Mans to Tours on the lower reaches of the Loire river. The D+90 objective was to extend the D+40 line of control to include the area of north-western France bounded by the Seine and Loire rivers connected by a line between Paris and Orléans.

To the COSSAC plan the 'Overlord' plan added two more beaches ('Sword' Beach at Lion sur Mer on the left and 'Utah' Beach at Les Dunes de Varreville on the right) so that five divisions could be landed in the first assault wave, joining the three airborne divisions already landed, against the four German divisions of General Erich Marcks’s LXXXIV Corps (of which only Generalleutnant Wilhelm Richter’s 716^th Division and Generalleutnant Dietrich Kraiss’s 352^nd Division would be fully engaged, as only parts of Generalleutnant Wilhelm Falley’s 91^st Luftlande-Division and Generalleutnant Karl-Wilhelm von Schlieben’s 709^th Division would come under attack after the 'Utah' Beach landings).

This meant that effectively eight Allied divisions would be attacking three German divisions, offering better chances of success than the COSSAC scheme, which had three Allied divisions assaulting two German divisions. Other advantages of the revised plan were the availability of seven Allied divisions to follow the five divisions of the assault wave, and the fact that the westward extension of the assault area to include 'Utah' Beach on the eastern side of the Cotentin peninsula opened the possibility of a rapid development to the north through the peninsula to Cherbourg even if the Germans managed to hold the line of the Vire river to prevent the other Allied forces sweeping to the west into the Cotentin peninsula.

In November 1943, when Adolf Hitler decided that the threat of an Allied invasion in France could no longer be ignored, Rommel was appointed inspector of coastal defences, and later as commander of Heeresgruppe 'B', the major ground formation charged with the defence of northern France. Rommel was of the firm belief that the only way to defeat an invasion was to launch the earliest possible armoured counterattacks on the invading forces while they were still on the assault beaches, and therefore wanted at least some of the Germans' armour placed close enough to the beaches to deliver an immediate counterattack. But Rommel’s authority was limited by the fact that he was subordinate to von Rundstedt. The latter was supported by General Leo Freiherr Geyr von Schweppenburg, commander of the Panzergruppe 'West' and himself supported by Generaloberst Heinz Guderian, the inspector general of Panzer troops, who all favoured a concentration of the Panzer divisions farther inland so that the primary Allied axis of advance could be determined and then a counterattack in force be launched to blunt it. The operational debate reflected the differing experiences in the war of the key decision-makers. von Rundstedt and Guderian had gained the bulk of their combat command experience when the Luftwaffe controlled the skies over the battlefield or, in the vast expanses typical of the Eastern Front, where neither side was able to claim air superiority over the entire front. Rommel’s experience was altogether different, however, for it was based on his command in North Africa, where the Luftwaffe and Regia Aeronautica had never been able to achieve anything more than local air superiority on limited occasions.

As the events during and after 'Overlord' were to prove, it was Rommel’s perception which was closer to the actuality of Normandy than that shared by von Rundstedt and Guderian. von Rundstedt and Guderian apparently never considered Allied air power in terms of the Luftwaffe’s heyday in 1939/41, and in fact Allied air power was now several magnitudes greater than anything the Luftwaffe had ever achieved. Rommel, however, was far better placed to appreciate the great disparity which the Germans would face against the Allied tactical air power’s huge capabilities.

In attempting to resolve the dispute, Hitler divided the six Panzer divisions in northern France. He allocated three directly to Rommel and placed the other three a considerable distance back from the beaches, and also ordained that these could not be released without the direct approval of Hitler’s operations staff.

The German air defence of the northern coast of France was vested in a mere 169 fighters since airfields in northern France had been seriously pummelled by constant Allied air attacks.

Hitler’s compromise was nonetheless a major reason for the Allied success at Normandy. Allied paratroopers were able to capture or damage the bridges which the German armour would require if it was to be used for a timely counterattack, and this prevented the launch of a coherent German counterattack as the Allied forces established their beach-heads.

There can be little doubt that the revised 'Overlord' plan was considerably superior to its COSSAC predecessor, but its development meant that the launch of the invasion had to be postponed from a time early in May to a time early in June 1944, the precise date of the invasion being determined by the need for a full or almost full moon for the nocturnal delivery of the three airborne divisions, coinciding with low water shortly after dawn so that the Allied air forces could provide tactical air support for the airborne forces and deal with any last German gun emplacements before the amphibious assault proper began at low water. This last was necessary as Rommel had developed the number and capability of the German obstacles and mines on the beaches, and these would only be exposed at low water.

The combination of these considerations indicated an invasion between 5 and 7 June 1944, so detailed plans were worked out by the staff of the 21^st Army Group, and troops began to move up toward their loading areas for 'Neptune' (iii), the assault operation which would take them across the English Channel to assault the coast of Normandy.

As these preparations were instituted, the Allies had two other tasks to undertake before the invasion. The first was the use of all available strategic as well as tactical air power to reduce the Germans' defence capability in North-Western Europe, albeit without any concentration on specific targets whose destruction would indicate Normandy as the designated invasion site. The second was the implementation of a series of complex dissimulation moves ('Bodyguard', 'Fortitude' and 'Skye') designed to make the Germans think that the landings would take place in the Pas de Calais or other regions, and thus maintain their forces in this region to the detriment of the garrison in Normandy.

The Allied strategic air forces in Europe had been put at Eisenhower’s disposal for the period up to 'Overlord'. Under the command of Lieutenant General Carl A. Spaatz, these strategic formations were Air Chief Marshal Sir Arthur Harris’s RAF Bomber Command in the UK and Spaatz’s US Strategic Air Forces in Europe (combining Lieutenant General James H. Doolittle’s 8^th AAF in the UK and Major General Nathan F. Twining’s 15^th AAF in Italy), all of which were to be used at Eisenhower’s behest to supplement the efforts of his own tactical air arms in England (under the command of the 'Overlord' air commander, Air Chief Marshal Sir Trafford Leigh-Mallory), namely Lieutenant General Lewis H. Brereton’s US 9^th AAF and Air Marshal Sir Arthur Coningham’s British 2^nd Tactical Air Force. From January 1944 onward these air armadas concentrated on targets in occupied Europe with emphasis (in order of priority) on aircraft production facilities, railways, V-1 sites and airfields in January; V-1 sites, airfields and railways in February; railways, aircraft production, V-1 sites, airfields and coastal fortifications in March; railways, airfields, V-1 sites, coastal fortifications and shipping in April; and railways, rolling stock, road bridges, coastal radar installations, V-1 sites and coastal fortifications in May. The object of this campaign was to halt the movement of German reserves, cut German lines of communication, destroy the V-1 sites which the Allies believed could jeopardise the landings, eliminate German aircraft and air facilities in France and the Low Countries, and destroy the coastal radars and fortifications that might warn of the invasion and then severely damage the assault forces at sea.

Less overt, but still as important, was the dissimulation programme, and in this field the Allies achieved a masterstroke, convincing the Germans of the existence of two major formations that did not in fact exist. The first of these was the US 1^st Army Group under the command of Lieutenant General George S. Patton, which the Germans believed, as a result of 'Fortitude South', was grouped in Kent and Sussex for a descent on the Pas de Calais with 25 infantry and armoured divisions plus five airborne divisions. The second phantom formation was the British 4^th Army, which the Germans believed, as a result of 'Fortitude North' and 'Skye', was assembling in Scotland under the command of Lieutenant General Sir Augustus Thorne for an invasion of Norway, where Generaloberst Nikolaus von Falkenhorst’s Armee 'Norwegen' had 11 divisions. His intuition told Hitler that the Allies would indeed land in either of these two places, and this certainty on the part of the German leader coincided with German staff appreciations about the threat to the Pas de Calais to prevent reinforcement of Normandy.

And it was just as important for the deception to be maintained after the implementation of 'Overlord', so that von Salmuth’s 15^th Army, deployed in the Pas de Calais and Belgium, was not used as a source of high-grade reinforcements for the 7^th Army. To this purpose two aircraft sorties were flown and two tons of bombs dropped in regions to the east of Le Havre for every one sortie and one ton of bombs in regions to the west of that port in the period immediately after D-Day: so convincing were these Allied deceptions that for seven weeks after D-Day the Germans thought that another (and larger) landing would be made in the Pas de Calais.

Other elements of the Allied deception plan were designed to mislead German intelligence as to the real strength of the Allies in the UK: the effect of this clever scheme was to persuade the Germans that the Allies had in the UK some 87 combat divisions (including eight airborne divisions), whereas the reality on 31 May was that the Allies had some 52 divisions, only 37 of them fit for continental operations.

So successful had been the Allied air offensive over northern France that Generalfeldmarschall Hugo Sperrle’s Luftflotte III had in this theatre a mere 420 aircraft to pit against an Allied aerial armada of some 10,521 combat aircraft (3,467 heavy bombers, 1,645 medium bombers, and 5,409 fighters and fighter-bombers), 2,355 transport aircraft and 867 gliders, the last two categories being used to transport some 27,000 men of the three Allied airborne divisions committed during the night of 5/6 June as the vanguard of the Allied assault.

The Allied assault forces were gathered in the southern part of the UK for their embarkation. On the left of the Allied assault Lieutenant General Sir Miles Dempsey’s British 2^nd Army was to land Lieutenant G. C. Bucknall’s I Corps ('Sword' and 'Juno' Beaches) and Lieutenant General J. T. Crocker’s XXX Corps ('Gold' Beach), while on the right Bradley’s US 1^st Army was to put ashore Major General Leonard T. Gerow’s V Corps ('Omaha' Beach) and Major General J. Lawton Collins’s VII Corps ('Utah' Beach). The objective of the four landings of the three eastern corps was by the end of the first day to secure a consolidated beach-head some 5 to 6 miles (8 to 9.5 km) deep between the mouth of the Dives river at Cabourg and the mouth of the Vire river at Isigny (and including the cities of Bayeux and Caen), while the VII Corps was to take an area on the eastern side of the Cotentin peninsula stretching from the mouth of the Vire river in the south to Quinéville in the north, and as far inland as Pont l’Abbé on the Douves river.

The flanks of the beach-head were to be secured first by airborne operations, in the east (in the I Corps' sector) by Major General Richard N. Gale’s British 6^th Airborne Division in 'Tonga', and in the west (in the VII Corps' sector) by Major General Matthew B. Ridgway’s US 82^nd Airborne Division and Major General Maxwell B. Taylor’s US 101^st Airborne Division in 'Detroit' and 'Chicago' respectively. Once these flanking operations had been launched, the seaborne assault forces were to arrive in three echelons.

In the assault wave the British I Corps was to land on 'Sword' Beach Major General G. T. Rennie’s British 3^rd Division (gathered in southern Sussex and embarked at Shoreham) supported by Brigadier G. E. Prior-Palmer’s 27^th Armoured Brigade and No. 41 Royal Marine Commando, and on 'Juno' Beach Major General R. F. L. Keller’s Canadian 3^rd Division (again gathered in southern Sussex and embarked at Shoreham) supported by Brigadier R. A. Wyman’s Canadian 2^nd Armoured Brigade and No. 48 (Royal Marine) Commando. The British XXX Corps was to land on 'Gold' Beach Major General D. A. H. Graham’s British 50^th Division (gathered in Hampshire and embarked at Portsmouth) supported by Brigadier H. F. S. Cracroft’s British 8^th Armoured Brigade and No. 47 Royal Marine Commando. Specialised armour was provided for these British formations by the 'funnies' of Major General Sir Percy Hobart’s British 79^th Armoured Division.

The US V Corps was to land on 'Omaha' Beach Major General C. Ralph Huebner’s 1^st Division (gathered in Dorset and embarked at Weymouth) supported by US Rangers. The VII Corps was to land on 'Utah 'Beach Major General Raymond O. Barton’s 4^th Division (gathered in Devon and embarked at Torquay and Dartmouth).

In the follow-up wave these corps were to be reinforced with their organic divisions, the British I Corps by Major General D. C. Bullen-Smith’s British 51^st Division (gathered in Essex and embarked at Southend), the British XXX Corps by Major General G. W. E. J. Erskine’s British 7^th Armoured Division and Major General E. H. Barker’s British 49^th Division (gathered in northern Essex and Suffolk, and embarked at Felixstowe), the US V Corps by Major General Charles H. Gerhardt’s US 29^th Division (gathered in Cornwall and embarked at Fowey) and Major General Walter M. Robertson’s US 2^nd Division (gathered in southern Wales and embarked at Swansea), and the US VII Corps by Major General Manton S. Eddy’s US 9^th Division (gathered in Somerset and embarked at Bristol) and Brigadier General Jay W. MacKelvie’s US 90^th Division (gathered in southern Wales and embarked in Cardiff).

In the follow-up corps wave the assault corps of the initial wave were to be reinforced by Lieutenant General Sir Richard O’Connor’s British VIII Corps, Lieutenant General N. M. Ritchie’s British XII Corps and Major General Charles H. Corlett’s US XIX Corps.

The first of the Allied formations to land were the airborne divisions, which began to arrive in Normandy during the night of 5/6 June. The British 6^th Airborne Division was not too badly scattered and managed to secure its primary objectives, but the US 82^nd and 101^st Airborne Divisions were woefully dispersed and were generally unable to secure their primary objectives behind 'Utah' Beach.

Of the amphibious assault formations, the US 4^th Division’s 8^th, 22^nd and 12^th Regimental Combat Teams arrived slightly to the south of their intended landing area at La Madeleine on 'Utah' Beach, but got ashore without undue difficulty and pushed inland toward Ste Mère Eglise and the main road from Carentan to Cherbourg, meeting increased resistance from the 919^th Grenadierregiment as it moved forward. By 24.00 the division had landed 21,328 men, 1,742 vehicles and 1,950 tons of stores, and had lost 197 men killed, wounded and missing. The US 1^st Division’s 18^th and 16^th Regimental Combat Teams on the left and 116^th and 115^th Regimental Combat Teams on the right on 'Omaha' Beach had a far harder time of it, and the division was totally unable to break through the defences of the 916^th Grenadierregiment to reach the road linking Isigny and Bayeux, some 3 miles (5 km) from the beach. During the night the US 29^th Division was landed in support of the US 1^st Division, but in the short term little could be achieved, and the US V Corps suffered some 2,000 casualties during the day before its men were able to push inland through German defences shattered by the gunfire of Rear Admiral A. G. Kirk’s Western Naval Task Force destroyers.

The Anglo-Canadian landings were opposed (from west to east) by the 726^th Grenadierregiment, 915^th Grenadierregiment and 736^th Grenadierregiment, and fared somewhat better than those of the Americans. In the sector of the British 50^th Division, Brigadier Sir A. G. B. Stanier’s 231^st Brigade, Brigadier F. Y. C. Knox’s 69^th Brigade, Brigadier E. C. Pepper’s 56^th Brigade and Lieutenant Colonel R. P. Lidwell’s (from 10 June Brigadier B. B. Walton’s) 151^st Brigade got off 'Gold' Beach and advanced some 6 miles (9.5 km) toward Bayeux by the end of the day. In the sector of the Canadian 3^rd Division, Brigadier H. W. Foster’s Canadian 7^th Brigade, Brigadier K. G. Blackader’s Canadian 8^th Brigade and Brigadier D. C. Cunningham’s Canadian 9^th Brigade had greater difficulty in landing, but then pushed forward from 'Juno' Beach some 8 miles (13 km) toward their objective, Carpiquet airfield. In the sector of the British 3^rd Division, Brigadier E. E. E. Cass’s 8^th Brigade, Brigadier K. P. Smith’s 185^th Brigade and Brigadier J. C. Cunningham’s (from 7 June Brigadier A. D. G. Orr’s) 9^th Brigade also came ashore without undue difficulty on 'Sword' Beach, and then pushed inland to relieve the 6^th Airborne Division and advance toward Caen and Troarn. The casualties of the 2^nd Army were some 3,000 men during 6 June.

The German riposte to the landings was patchy, not helped by the fact that Marcks was away in St Lô for his 53^rd birthday and Rommel was in Germany for a conference, with Generalleutnant Dr Hans Speidel, the Heeresgruppe 'B' chief-of-staff, deputising for him in France. Nevertheless, word of the invasion passed rapidly from the LXXXIV Corps to the 7^th Army to Heeresgruppe 'B' and to the Oberbefehlshaber 'West', who ordered SS-Gruppenführer und Generalleutnant der Waffen-SS Fritz Witt’s 12^th SS Panzerdivision 'Hitlerjugend' and Generalleutnant Fritz Bayerlein’s Panzer-Lehr-Division to ready themselves for a rapid counterattack while he cleared the matter with the Oberkommando der Wehrmacht and Hitler. Hitler refused to let von Rundstedt commit this powerful armoured force at what could have been the decisive moment, however, and instead ordered that no overt moves were to be made until there had been time for the situation to clarify itself. Thus the local armoured formation, Generalleutnant Edgar Feuchtinger’s 21^st Panzerdivision, was kept immobile until 14.30, and SS-Oberstgruppenführer und Generaloberst der Waffen-SS Josef Dietrich’s I SS Panzerkorps (12^th SS Panzerdivision and Panzer-Lehr-Division) until 17.00.

Speidel warned Dollmann that the daylight movement of the I SS Panzerkorps would result in heavy losses from Allied tactical aircraft, and this proved to be the case, establishing an ominous precedent for the Germans in the months to come. The two divisions found it difficult to concentrate, and then suffered heavy losses to the activities of Allied fighter-bombers (many fitted with devastating rocket armament) as they moved toward the fighting, arriving only on 8 and 9 June respectively.

The 21^st Panzerdivision was in army group reserve closer to the sea, and was able to intervene more rapidly, initially with its infantry units and then with its armour in support of the 716^th Division. During the afternoon of 6 June the 21^st Panzerdivision pushed forward into the area between 'Juno' and 'Sword' Beaches, advancing almost as far as Douvres before it was pushed back again, almost out of petrol and having lost 40 of its 197 tanks and assault guns. Delays imposed by Hitler had thus cost the Germans their only real chance of driving the Allies back into the sea.

Each side was now beginning to move in major reinforcements. The 7^th Army was assigned the task of dealing with the US 1^st Army. The staff of Geyr von Schweppenburg’s Panzergruppe 'West' (eventually commanding the XLVII Panzerkorps, I SS Panzerkorps and II SS Panzerkorps, but currently limited to three Panzer divisions), and under the personal supervision of Rommel, tried to handle the British by retaking Bayeux and pushing on to the sea before destroying the two groups into which the British would have thus been divided. It was a vain hope, for by the morning of 10 June the Allies had consolidated their beach-head into a single cohesive lodgement soon to be supported by two 'Mulberry' artificial harbours. At this time the Allied front ran from Crisbecq some half-way up the eastern side of the Cotentin peninsula to Ouistreham at the mouth of the Orne river, and contained 10 infantry divisions, three airborne divisions and three armoured divisions.

'Neptune' (iii) had worked magnificently as the first stage of 'Overlord', and the Allies were in France to stay, with the planners now working on the optimum way for the British to draw in the German reserves (especially the armoured formations) so that the Americans could eventually break out in the west (in 'Cobra'). Thus there was still some dire fighting to be undertaken around Caen and south of Bayeux, while the US 1^st Army got the ball rolling once more with the seizure of the Cotentin peninsula. By 17 June the 9^th Division, flanked on the north by the US 90^th Division and on the south by the 82^nd Airborne Division, had driven to the west from Ste Mère Eglise through Generalleutnant Heinz Hellmich’s (from 17 June Generalmajor Bernhard Klosterkemper’s) 243^rd Division and Generalleutnant Eugen König’s 91^st Luftlande-Division to reach the western coast of the Cotentin peninsula between Carteret and Portbail. From this line the 9^th Division, Major General Ira T. Wyche’s 79^th Division and the 4^th Division then advanced to the north to take Cherbourg on 27 June. German resistance on the Cotentin peninsula ended on 30 June in the Cap de la Hague, and the Allies could then be reinforced and supplied through a major port.

Once the beach-heads had been established, the assemblies and components of the two 'Mulberry' artificial harbours were towed across the English Channel and assembled, the two harbours being made operational around D+3: one was constructed at Arromanches on 'Gold' Beach by British forces, and the other at 'Omaha' Beach by US forces. The latter harbour was destroyed in severe storms around D+13. Some 9,000 tons of matériel were landed daily at the Arromanches harbour until the end of August 1944, by which time the port of Cherbourg had been secured by the Allies and begun to return to service.

In overall terms the German defenders positioned on the beaches of Normandy put up relatively light resistance, being ill-trained and short of transport and equipment, and having also been subjected to a week of intense bombardment. An exception was Kraiss’s 352^nd Division, moved earlier by Rommel from St Lô to defend the stretch of coast including 'Omaha' Beach. The tenacity of this division’s defence, and perhaps also the indication by Allied intelligence that there would be only two battalions of Richter’s 716^th Division there, was responsible for the high casualty rate suffered by the US forces on 'Omaha' Beach. Other German commanders took several hours to be sure that the reports they were receiving indicated a landing in force, rather than a series of raids. Their communication difficulties were made worse by the absence of several key commanders.

The scattering of the US airborne forces also added to the confusion, as reports were coming in of Allied troops all over northern Normandy. Despite this, the 21^st Panzerdivision mounted a concerted counterattack, between 'Sword' and 'Juno' beaches, and succeeded in reaching the coast. Stiff resistance by anti-tank gunners, and fear lest they be cut off, then caused the German armoured force to withdraw before the end of 6 June.

The Allied invasion plan had called for the capture of Carentan, St Lô, Caen and Bayeux on the first day, with all the beaches except 'Utah' linked into a single lodgement inside a front line 6 to 10 miles (10 to 16 km) inland from the beaches. In practice none of these had been achieved. However, overall the casualties had not been as heavy as some had feared, and the beach-heads had withstood the expected counterattacks.

Priorities in the days following the landings for the Allies were to link the beach-heads, take Caen and capture the port of Cherbourg to provide a secure supply line. The 12^th SS Panzerdivision 'Hitlerjugend' attacked the Canadian forces in the 'Juno' beach-head on 7/8 June, inflicting heavy casualties, but was unable to break through. Meanwhile, the beaches were being linked: 'Sword' Beach with 'Juno' Beach on 7 June, 'Omaha' Beach with 'Gold' Beach on 10 June, and 'Utah' Beach with the rest of the Allied lodgement on 13 June. The Allies were actually reinforcing their side of the front faster than the Germans were achieving on the other side of the front. Although the Allies had to land everything on the beaches, Allied air superiority and the previous destruction of the French railway system made every German troop movement slow and dangerous.

The country behind 'Utah' and 'Omaha' Beaches was characterised by bocage: ancient banks and dense hedgerows, up to 10 ft (3 m) thick, spread 110 to 220 yards (100 to 200 m) apart and impervious to tanks, gunfire and vision, and thus possessing the makings of ideal defensive positions. The US infantry made slow progress and suffered heavy casualties, as they pressed toward Cherbourg. The airborne troops were called on again and again to restart a stalled advance.

Hitler expected the Cherbourg garrison to resist to the end and thus to deny the port to the Allies, but Cherbourg’s commander surrendered on 26 June.

Rightly believing Caen to be the 'crucible' of the battle, Montgomery made it the target of three separate attacks between 7 June and 1 July, before it was bombed on and attacked on 7 July in 'Charnwood'. Seeking a decisive break-out into the open country which would permit an advance to Paris, Montgomery launched a breakthrough attempt at Villers Bocage on 13 June, and between 18 and 20 July Montgomery launched 'Goodwood' (i) as a major offensive from the Caen area with all three British armoured divisions. Only indifferently planned, 'Goodwood' (i) was eventually stopped by determined and improvised resistance by the 1^st SS Panzerdivision and 12^th SS Panzerdivision, heavy Flak units, and Generalmajor Karl Sievers’s 16^th Felddivision (L). The British tank casualties were very high, but the battle had the important effect of persuading the Germans to leave their armour reserves committed in the eastern (British) sector, and therefore unavailable for 'Cobra', the US break-out in the west on 24 July.

'Cobra' succeeded beyond all expectation, and the advance guard of the VIII Corps rolled into Coutances, at the western side of the Cotentin peninsula, on 28 July, penetrating the German line for the rest of Patton’s new 3^rd Army to advance through into north-western France. The bulk of German resistance in the region was finally eliminated on 21 August with the successful closure of the 'Falaise gap' by Canadian, Polish and US troops. The clandestine French resistance forces in Paris rose against the Germans on 19 August, and Général de Division Philippe François Marie Jacques Leclerc de Hauteclocque’s French 2^nd Armoured Division, along with the US 4^th Division, pressing forward from Normandy, received the surrender of the German forces there and liberated Paris on 25 August.

Although ultimately successful, the Normandy landings were extremely costly in terms of men, military supplies and equipment. The failure of the British 3^rd Division to take Caen, an overly ambitious target, on the first day was to have serious repercussions on the conduct of the campaign for something more than one month, seriously delaying any forward progress. The fortuitous British capture of Villers Bocage, followed by its loss after the failure to reinforce it, was again to hamper any attempt to extend the Caen bridgehead and push on. By D+11, 17 June, the assault had stagnated. Much of the problem was attributable to the nature of the bocage terrain in which much of the post-landing fighting took place.

Ultimately, 'Overlord' succeeded in its objective by sheer force of numbers. Many more troops and equipment continued to come ashore after D-Day. By the end of July 1944, some 1 million Allied troops, mostly British, Canadian and US were ensconced in Normandy. The success of the battle opened up the long-awaited Western Front, causing Germany to divert much-needed manpower and resources from the east and Italian fronts to fight on the new battlefield in North-West Europe.

The lodgement established at Normandy was vital for the Western Allies to bring the war to the western border of Germany. By this time the Soviet forces had the capacity to crush Germany in Europe on their own, and therefore a western invasion was not strictly required to encompass the military defeat of Germany. On D-Day, the Soviet army was steadily advancing toward Germany and four-fifths of the German forces were deployed on the Eastern Front. In France, the Allies faced only about 20% of the German army. The new second front, however, certainly diverted German resources and attention from the Eastern Front, and thus shortened the war. Given the Soviets' later domination of eastern Europe, it is arguable that had the Normandy invasion not occurred there might conceivably have been a complete occupation of northern and western Europe by communist forces, and to this extent the US and British presence helped define the extent to which communism would spread into Europe.