Army Group A
Army Group A was the name of three distinct army groups of the Heer, the ground forces of the Wehrmacht, during World War II.
The first Army Group A, previously known as "Army Group South", was active from October 1939 to June 1941 and notably served in the Battle of France as the decisive army group in the implementation of the "Sickle Cut" military plan that inflicted crushing subsequent defeats on the French armed forces at occasions such as the Battle of Sedan, Battle of Boulogne and Battle of Dunkirk and that ultimately led to the Armistice of 22 June 1940. Army Group A was subsequently used in the German occupation of France and temporarily became the first Oberbefehlshaber West in German-occupied France. It was eventually replaced in this function by Army Group D and redeployed to German-occupied Poland in preparation for Operation Barbarossa. At the commencement of that attack, Army Group A was renamed "Army Group South" on 22 June 1941, ending the first deployment.
The second Army Group A was inserted into the German line on 7 July 1942, when Army Group South was split during the German 1942 summer offensive into Army Group B in the north and Army Group A in the south. It advanced towards the Terek river, but was eventually forced to withdraw by the winter of 1942/43, concurrent with the decisive defeat of Army Group B in the Battle of Stalingrad. Initially confined to the Kuban bridgehead and the Crimean peninsula, Army Group A fought a rearguard action against the Red Army during its westwards withdrawal through Ukraine. On 2 April 1944, it was renamed "Army Group South Ukraine".
The third and final Army Group A came into existence on 23 September 1944, when the previous Army Group North Ukraine was renamed "Army Group A". It existed for about five months that were marked by constant withdrawals from the advancing Red Army and eventually left Army Group A at the Oder river line. On 25 January 1945, Army Group A was one of several army groups to be renamed, receiving the designation "Army Group Center". No subsequent Army Group A was formed.
First deployment, 1939–41
Army Group A was formed, through the redesignation of Army Group South, on 26 October 1939 in the central sector of Germany's western frontiers, along the France–Germany border and Belgium–Germany border, in the broader area of the Eifel and Hunsrück mountain ranges. Under its previous name, the army group had fought in the Invasion of Poland in September and October 1939. The initial commander and chief of staff of Army Group A were the same persons who held these portfolios during the time of Army Group South in Poland, Gerd von Rundstedt as commander and Erich von Manstein as chief of staff.Preparations for the Battle of France
Enthusiasm among the higher echelons of Army Group A for a repetition of the armored thrusts of the Poland Campaign was initially limited; Army Group A chief of staff Georg von Sodenstern predicted as late as 5 March 1940 that a repetition of the swift advances through what was estimated to be a well-developed French defensive line was less than likely.Nonetheless, the military preparations that the Wehrmacht ultimately settled for in regards to the upcoming Western Campaign was in accordance with the "Manstein Plan", developed by then-chief of staff of Army Group A Erich von Manstein on his post in the Koblenz Electoral Palace, where the HQ of Army Group A was then located. Manstein had developed the first drafts of his conception in late October 1939 upon his first receival of the original deployment plan against France. Whereas this original plan envisaged to place the focus of operations with the northernmost army group, Army Group B, Manstein instead demanded that the focus be shifted towards Army Group A and the German center. In total, Manstein issued seven memoranda arguing for his proposal in various ways. As Manstein's insistence annoyed the army's general chief of staff, Franz Halder, he was removed from the position of Army Group A chief of staff and instead moved to the command of the upcoming XXXVIII Army Corps, thus eliminating him from a major command post in the upcoming campaign. The Mechelen incident in January 1940, which provoked a response by the Allied armies and allowed the Germans to observe the Allied defensive movements, gave additional credibility to the Manstein Plan, as it made the encirclement of Allied forces in the Low Countries appear plausible.
The Manstein Plan found its way to Hitler's desk through the interventions of Günther Blumentritt, Henning von Tresckow and Rudolf Schmundt, and Hitler received Manstein for a private meeting on 17 February 1940 in Berlin. Hitler, who found thought experiments that he had himself had in the previous weeks confirmed in Manstein's more elaborate presentation and ordered its implementation, resulting in a complete shift of plans by OKH, placing the German Schwerpunkt southwards in accordance with the Manstein Plan. Nonetheless, even though Franz Halder was eventually swayed, many detractors remained. Especially the commander of Army Group B, Fedor von Bock, believed the change of military focus to be an irresponsible gamble. Additionally, the implementation of the plan was not helped by the fact that Halder's intrigue to replace Manstein had resulted in the appointment of Georg von Sodenstern as chief of staff of Army Group A. A conservative-minded planner, von Sodenstern had initially been selected by Halder precisely because he opposed the Manstein Plan, and was now left to oversee its realization. Indeed, there were now serious reservations in the upper echelons of Army Group A whether or not the motorized and armored formations should truly be in the vanguard during the advance, or whether it would not be preferable to attack with the infantry first. Such doubts were voiced by von Sodenstern, Blumentritt, and notably by army group commander Gerd von Rundstedt himself. This scepticism was not shared by the advocates of rapid armored assaults, such as Heinz Guderian of XIX Army Corps.
Army Group A would be equipped with 4th Army, 12th Army, 16th Army and Panzer Group Kleist, commanded by generals Kluge, List, Busch and Kleist, respectively. This assignment left the army group with four out of the eight field-army level commands assigned to the three army groups along the western frontier. Each of these armies as well as the panzer group were equipped with three army corps each, placing the army group at a total of twelve army corps. Additionally, Army Group A also received the concentration of German armored and motorized formations, as 5th and 7th Panzer Divisions were assigned to 4th Army and 1st, 2nd, 6th, 8th and 10th Panzer Division and XIX Corps ) assigned to Panzer Group Kleist. Additionally, Panzer Group Kleist also received the 2nd, 13th and 29th Motorized Infantry Divisions. In total, this left Army Group A with seven panzer divisions and three motorized infantry divisions, compared to just three each for Army Group B further north and none of either type for Army Group C in the south. Whereas Army Groups B and C had and 17 divisions, respectively, Army Group A was equipped with divisions, leaving it as the clear Schwerpunkt of the German thrust. Additionally, most of the 42 available reserve divisions were earmarked to support Army Group A rather than either of the other two army groups. The overall task of Army Group A was to breach the Meuse river line between the cities of Sedan and Dinant using a rapid breakthrough of motorized formations and to then advance towards the Somme river estuary. In this, 4th Army was to cross the Meuse at Dinant, the 12th Army at Sedan. The 16th Army was to protect the southern flank from Allied counterattack, whereas the 2nd Army, initially posted in reserves, would be used to follow the advancing 4th and 12th Armies. Once the latter turned towards the Somme estuary, 2nd Army could then be used to cover the spaces vacated by the two other armies. Panzer Group Kleist was to carry the momentum and speed of the assault, receiving a total of 41,140 motorized vehicles including 1,222 tanks spread across two armored corps and one motorized infantry corps, with a total personnel strength of 134,370. This left Panzer Group Kleist as by far the strongest single motorized formation ever used in warfare up to this point. However, Panzer Group Kleist fell victim to a strange compromise that was caused in no small part by its novelty factor: Rundstedt allowed the panzer group to initially operate autonomously, but placed the condition that it would be placed subservient to either of the infantry armies if it managed to catch up to the panzer group. As a result, the leadership of Panzer Group Kleist had a strong incentive during the campaign for single-minded and daring operations to preserve their organizational autonomy.
Battle of France
During the Battle of France, Army Group A was pivotal in the implementation of the German breakthrough in the central sector of the front, with Army Group A forces crossing the Ardennes mountain range, and then swiftly turning northwestwards to rush towards the English Channel and trap the Allied armies in the Low Countries. In this, Army Group A would cooperate with Army Group B and Army Group C, all under the joint supervision of OKH.4th Army advanced on the army group's right flank from the Monschau sector along the Liège—Namur axis as well as towards Dinant. To its left, 12th Army stood in the army group's center, with its initial thrust directed from the Prüm sector via northern Luxembourg towards Neufchâteau and then towards the Meuse river. Furthest in the south, the 16th Army held the army group's left flank and aimed to advance from the Trier—Merzig sector over Luxembourg City towards Longuyon. In its entire sector, Army Group A developed a large numerical advantage, advancing its own 45 divisions through territories held by only 18 enemy divisions.
Within days of the beginning of the campaign, the troops of Army Group A achieved what one of the army group's staff officers, Günther Blumentritt, would later refer to as a "three-fold miracle": The Allied air forces failed to attack the lengthy tank columns that were stuck for hours on end in traffic jams trying to cross the Ardennes, the Germans succeeded with high speed and low casualties to cross the Meuse river with the breakthrough in the Battle of Sedan, and the German tank divisions finally won a stunning victory in what was at times a more than reckless advance towards the channel coast, dangerously abandoning the cover of the German thrust's flank against a potential Allied counterattack that never materialized.
There was a repeated tendency during the early days of the campaign where the Army Group A high command and the political leadership would advocate caution, but their instructions overruled and ignored by the divisional and corps commanders on the ground. Georg-Hans Reinhardt of XXXXI Corps ignored a direct oder by the army group and instead advanced with his troops out of their bridgehead at Monthermé. A similar action was undertaken by Heinz Guderian of XIX Corps, who on 14 May was dissatisfied with the prospect of Army Group A leadership using his tanks to safeguard the bridgehead rather than to exploit the momentary disarray in the French army's rear. The leader of the panzer group, Ewald von Kleist, found himself in the difficult situation of mediating between his superior army group and his subordinate corps commanders; Kleist had initially covered Reinhardt's autonomous actions but was forced on 17 May to give a definitive holding order to Guderian, as Hitler personally had decreed a deceleration of the armored advance. This order remained in place until 19 May.
When the operational delay of 17 May was revoked on 19 May, the tanks' thrust into the Allied rear continued. There was temporary panic among Army Group A higher-ups when on 21 May, a British attack hit the exposed German flank at Arras, resulting in the Battle of Arras. This attack was however repelled within hours. The first German forces had already reached the channel coast at 02:00 in the morning on 20 May, when 2nd Rifle Regiment of 2nd Panzer Division reached Noyelles-sur-Mer. This left the northern sector of the French Army, the Belgian Army and the British Expeditionary Force cut off in the Low Countries.
By 24 May, the Germans had encircled the critical channel ports of Boulogne-sur-Mer and Calais and were just 15 km off the last partially unobstructed port that the encircled Allied forces could use, Dunkirk, where the Allies began to rapidly implement an evacuation of their forces. Particular historical interest has been given to a sequence of events on 24 May 1940 known as the "halting order", where the armored formations were ordered to halt outside of Dunkirk and to instead prioritize infantry formations in the Battle of Dunkirk. Popular imagination of both German and Western Allied postwar observers was captured by the idea that the German tanks might have inflicted horrific casualties on the encircled and tightly-packed Allied infantry, if they had not been stopped by undue meddling by higher military command. Hitler had personally insisted on the preservation of the remaining tank forces on 24 May, overruling even Walther von Brauchitsch, the commander-in-chief of the German army, after a worrying 23 May report by Ewald von Kleist had placed the casualties of his panzer group at "over 50%". Hitler in this concurred with the leadership of Army Group A and went against the intuition of von Brauchitsch, who even attempted to transfer the 4th Army away from Army Group A to insist on his own vision. Due to a coincidence, Hitler happened to be present at Army Group A headquarters on 24 May, and overruled Brauchitsch's instructions, implementing instead the "halting order". The halting order was revoked on 26 May and Dunkirk captured on 4 June. While the British army had been forced to leave behind much of its heavy equipment, some 340,000 British and Allied soldiers were successfully evacuated out of Dunkirk.
After the Allied evacuation at Dunkirk, Army Group A tuned southeast and advanced in the general direction of the Vosges mountains and the France–Switzerland border, thus encircling the static French forces positioned along the Maginot Line.