Corps - The Great War

Next to the Army, the largest fighting unit was the Army Corps. Nine Army Corps were organized as part of the three Armies of the A.E.F. Each Army Corps is commanded by a major general, and consists of five or more divisions plus about twenty-five auxiliary units. In an offensive three divisions are usually used in the front lines and one or two divisions are held in reserve. The auxiliary units of an Army Corps include Corps Troops and Corps Headquarters Troops, a Pioneer Infantry and an Engineer regiment, a troop of Cavalry, an Artillery park and corps Artillery, a Balloon company and an Aero squadron, Corps Military Police, a Motor Supply Train, Ordnance and Motor repair shops, mobile veterinary hospitals, ambulance companies and field hospitals.1 The war strength of an Army Corps is approximately 120,000 men. An American division numbers 30,000 men, and a corps consists of six divisions, two of which play the part of reserves. With auxiliary troops, air squadrons, tank sections, heavy artillery, and other branches, a corps numbers from 225,000 to 250,000 men.

The army corps was formed with six divisions. Four of these were to be employed in active service, one was for replacement, one for depot. The army corps also included some non-divisional units, practically forming a total of 6,050 officers and 170,000 men. It must not be supposed that this formation of the army corps was absolutely rigid and immutable, and one in which General Pershing admitted of no modification; on the contrary, the constitution of the army corps had as a principal object to supply a permanent base of computation for the calculations necessitated by the priority schedules. In this manner the proper number of troops with their auxiliaries could be reckoned upon by the transportation experts.

In military forces the command is made up of a number of included commands. These may be organized alike or may have different organizations and equipment, and perform different functions, for example in an Army Corps, the Corps Commander has five division commanders, five to perform the major tasks allotted to the corps, and in addition there is a group of ten or twelve commanders of the corps troops such as Corps Artillery, Engineers, Tanks, Air Service, etc., whose tasks are incidental to the activities of the divisions. These ten or twelve commanders of the corps troops were the Technical Staff of the commanding officer, but in the majority of cases they deal directly with the General Staff and keep the General Staff informed of the use and requirements of their special troops.

The original idea of replacement for the Army was worked out so as to give to each corps six divisions; four combat and two replacement divisions. One of these replacement divisions was to remain in a training area and train replacements in both men and officers-from privates to generals. The sixth division of the Corps was to be the Depot Division, situated somewhere near the seacoast where it would receive and organize drafts from the United States. This scheme, however, was never fully developed, but it formed the basis of the training system of the AEF.

The corps were to be kept mobile, whereas the schools worked best when stationary; and as the Replacement Division of the corps was stationary, it was decided that the Corps Schools should be situated with this division, and thereby the labor and demonstration troops would be available to the school. The need for coordination in these Corps Schools led to the establishment of a group of Army Schools, to furnish instructors for the Corps Schools, so that the Corps Schools could train officers rapidly, and send them back to their commands. Students graduating with distinction from Corps Schools were sent to Army Schools.

During all the time since the Germans had begun their offensive in March, 1918, there was no American Army. Instead the various American Divisions were scattered far and wide along the front as parts of many British and French Armies. General Pershing relinquished the actual command of all the American combat troops in France, when Marshal Foch was made Commander-in-Chief of all the Allied forces. At that time it was a necessity for many reasons: the Americans lacked Army and Corps Staffs and Corps troops-particularly guns, aeroplanes, horses and trucks. Then, too, the Allied morale was badly in need of the visual support which could best be given by having the Americans mix in the hardest fighting on every front; but most of all, for the reason that the Allies were badly in need of men.

By 08 August 1918, however, all these conditions had changed. American Generals and Staffs had received the training of actual experience; American divisions had fought on every front and with every army; the great American mid-summer troop movement from the United States had given superiority in numbers to the Allies; the Germans were once more on the defensive and the crying need for support of the French and British Armies, both moral and physical, was no more. Accordingly Marshal Foch decided that the time was at hand for the American Divisions to be withdrawn from the Allied Armies and assembled for the first time together as one army, the First American Army, under General Pershing.

As the line then stood on the tenth of August, 1918. American troops were holding practically the entire southern side of the great St. Mihiel Salient. The line held extended from the lakes and swamp, just east of Apremont, east almost as far as Clemery, which was practically the front north of Toul and Nancy. This was the American Sector. The ist Division had taken over the trenches from the French in January, 1918. At that time the plan was gradually to develop this into a sector for an American Corps, and later enlarge it for an American Army.

The serious threat at Paris by the Aisne offensive of May 27th to June 4th, 1918, resulted in a number of American divisions being brought together at ChateauThierry. On June 6th, as the result of Pershing's insistence, Petain agreed that an American corps sector should be organized in this district. The I, the II, the III, and the IV Corps Headquarters had meanwhile been organized, one after the other, so that they would be prepared to take command when the various American corps were formed. As yet these corps headquarters had had nothing to command. Pershing now ordered the I Corps Headquarters to Chateau-Thierry to be ready to take command when the French turned this sub-sector over. Pershing still believed, as he had believed and urged from the beginning, that the Woevre was the field where the big American effort should be made. He accordingly put the IV Corps Headquarters in the vicinity of Toul, though at the time it had nothing to command.

Pershing's long-continued effort bore its first fruit on July 4th, 1918. On that day the I Corps Headquarters took over the tactical command of the Chateau-Thierry sector occupied by the American 26th Division and the French 26th Division. There were now more than 900,000 American soldiers in France. There were eight American divisions in the front line. Just one American division was under the command of an American corps headquarters.

Following an announcement on 01 July 1918 that the first American Army corps was just being organized, there came on July 13 the news that General Pershing now had so many properly trained divisions at his disposal that he had been able to form three army corps, which did not include several hundred thousand men training in France and Great Britain and on the way across the Atlantic. Each army corps numbered from 225,000 to 250,000 men, so that approximately 700,000 Americans were actually on the battlefront. The three corps were designated the 1st, 2d, and 3d. The 1st was composed entirely of veteran troops, including the 1st and 2d Divisions of regulars and the Marine Corps Brigade, which distinguished itself in the ChateauThierry-Soissons sector.

By the November 1918 armistice nine army corps existed or were in process of formation:

1. The First Corps, under General Liggett, which had already taken part in active operations in the Marne and Vesle campaigns, and was at this time between Saizerais and Toul. This corps possessed its organic artillery and a portion of its services of the rear.
2. The Second Corps may be simply noted here as operating upon the British front. General Read, who was in command, had established Jiis headquarters at Fruges where he administered the American divisions which were in line or else undergoing instruction in the British zone.
3. The Third Corps, commanded by General Bullard, still remained at Chateau-de-Fresnes, south of the Vesle, from whence they were soon to be transported to Souilly, near Verdun. Like the First, the Third Corps had already been proven; like it it also possessed its own artillery and other services, and might therefore be considered as ready for action.
4. The Fourth Corps of much more recent formation was under the orders of General Dickman, former commander of the Third Division; his staff was newly assembled at Toul with supervision over operations in the southern Woevre sector.
5. The Fifth Corps had been for several days at BenoiteVaux, near Dieue-sur-Meuse. Its chief, General Cameron, lately at the head of the Fourth Division, during operations between the Marne and Vesle, had but recently constituted his staff.
6. The Sixth Corps which was at Bourbonne-les-Bains recently organized and consequently not ready for action. It was commanded by General Bundy, lately at the head of the gallant Second Division which had checked the enemy before Chateau-Thierry. The Sixth Corps did not participate in the fighting. After the armistice it consisted of the Seventh, Twenty-eighth, and Ninety-second Divisions and was engaged in salvage work on the battlefields.
7. The Seventh Corps was operating in the Vosges under General Wright, formerly commanding the Fifth Corps, with headquarters at Remiremont. The Seventh Corps was organized to form part of the Third Army and consisted of the Fifth, Eighty-ninth, and Ninetieth Divisions, being stationed in Luxembourg as a reserve for the troops in the occupied German territory.
8. The Eighth Corps in the reorganization after the armistice consisted of the Sixth, Seventy-seventh, and Eighty-f1rst Divisions.
9. The Ninth Corps consisted of the Thirty-third and Thirty-fifth Divisions and was engaged in salvage work on the battlefields.