SEPH (1856– ), French soldier, was born on May 24, 1856 at Cauchy la Tour (Pas de Calais). He was commissioned from St. Cyr 1878, passed in due course through the t cole de Guerre, filled various staff appointments, including that of instructor at the Ecole de Guerre, and was promoted colonel in 1910. At the outbreak of the World War he was commanding an infantry regi ment, but he was immediately given a brigade and then a division, and acquitted himself so well during the opening weeks of the struggle that he was advanced to the command of the XXXIII. Army Corps in Artois on Oct. 25, 1914. He greatly distinguished himself on the occasion of the French offensive near Arras in May 1915, where his corps completely broke through the German position, though exploitation proved to be impossible for want of reserves. On June 21, 1915 he was given command of the II. Army, which under his orders carried out on Sept. 25, 1915 the great attack in Champagne. After this action Gen. Petain wrote a remarkable Rapport sur les operations de la Ile. armee en Champagne et enseignements a en tirer. This contained the prin ciples of a new tactical doctrine, and was published in the Ar chives de la Grande Guerre, No. Io, pp. 5-30.
After the battle of Champagne, the staff of the II. Army was withdrawn from the front, and was thus available at the moment when the Germans were attacking Verdun on Feb. 21, 1916. It was then that the task of stopping the advance of the German crown prince was entrusted to Petain.
His first task was to organize the battle zone. He fixed a line of defence from Bras to Douaumont: this line had to be held at all costs, and under cover of it he divided up the ground to be held in sections which were duly laid out and equipped. It was largely owing to the system and energy of Petain that Verdun was saved (see VERDUN, BATTLES OF). On May 1, 1916 he was given the command of the centre army group, of which the IV. Army, on the left, took part in the great offensive of April 16, 1917. On April 28 he was appointed chief of the general staff at the Ministry of War in Paris; and on May 15 he replaced General Nivelle as Commander-in-Chief of the armies in the field.
The French army at that time was faced with a grave crisis, not excluding mutinies. Petain did his utmost to remove the
special causes of discontent, such as the irregularity of leave, and the inequality between units in their tours of duty in the trenches. He also saw to it that soldiers on leave were not exposed to dangerous influences or neglect, and he renewed the confidence between the combatants and their leaders. By means of reforms rather than measures of repression, he succeeded from the month of June onwards in having the army completely in hand. In directive No. 1 he informed the army group and army corn manders that they must limit themselves provisionally to pre paring attacks with only limited objectives with the object of wearing out the enemy reserves. In directive No. 2, which was issued in the second fortnight of June, he reconstructed the training of the troops. In directive No. 3, at the beginning of July, he laid down the method of distribution in depth. The key note of the limited operations outlined by his directive No. i was to be thoroughness of organization and high proportion of fire-power, so as to give the maximum result with the minimum risk. Such were the characteristics of the action of the I. Army in Flanders, July 15-31; the II. Army before Verdun, Aug. 13-25 (see VERDUN, BATTLES OF) and of the VI. Army at Malmaison, Oct. 17-26.
Late in 1917 it became apparent that owing to the defection of Russia a formidable German offensive would be launched in the spring of 1918 on the western front. With this in view, Petain studied the possibilities of surprise by placing reserves within reach of the threatened points. On Feb. 22, 1918 he and Sir Douglas Haig agreed to give each other mutual assistance. On March 21 when the Germans had just attacked General Gough's Army with great violence, Petain hurried forward the V. Corps which was in reserve behind his left wing. On the 22nd Haig having requested the intervention of the French army, Petain pushed forward the extreme left or 125th Division of the VI. Army towards the field of battle, where it arrived during the night March 2 Other French units were speedily added in order to assist the British, and these formed successively the III. Army and then the I.