In 1814 Blucher went round the Argonne. In 1870 the Third Prussian Army (the Army of the Meuse) crossed it without much difficulty. THE GREAT WAR (1914-1918) In August, 1914, in spite of their success on the Meuse, the French Third and Fourth Armies were ordered by Joffre to make a general retreat towards the south. The Third Army, under Sarrail, pivoting on its right, now rested on Verdun. Facing it was the German Vth Army, under the Crown Prince. The German forces, following the retreat of the French Armies, slipped in on either side of the thick woods of the Argonne, along the Valleys of the Aisne and the Aire. On September 5, under Joffre’s orders, the retreat came to an end, and the great battle, which was to save France, began. After six days of violent fighting (see Part III--The Revigny Pass--of the Battle of the Marne, 1914), the Crown Prince’s troops, under pressure of the French Third Army, retreated along both flanks of the Argonne; but during the latter half of September, they came to a stand, after reaching and consolidating the following positions: on the east, Montfaucon, commanding the ground between the Aire and the Meuse; Montblainville and Varennes, commanding the Valley of the Aire; on the west, Binarville, Servon, and Vienne-le-Château, commanding the Valley of the Aisne. A fierce and prolonged battle then began. The French troops, held on the flanks, pushed on into the forest, in an endeavour to cut the enemy’s transverse lines of communication, which consisted of two main roads from east to west (see map, p. 8). (1) The main road from Varennes to Vienne-le-Château, _via_ the Four-de-Paris, where a road running north-south branches, crossing at Les Islettes, the “National Road,” and the railway from Châlons-sur-Marne to Verdun, via Sainte-Menehould. (2) The wide forest road which, two or three kilometres to the north, runs almost parallel to the first road, from Montblainville to Servon-Melzicourt, _via_ Bagatelle, and across the Bois de la Gruerie. The Germans, on their part, made every effort to maintain their lines of communication. Moreover, they had not given up the hope of encircling and taking Verdun. Through the transverse valleys of the Aire and the Aisne, and the central passage of the Biesme, they threatened to cut the Châlons-Verdun Railway, and thereby separate the Army of Champagne from that of Verdun. The importance of the Argonne position thus becomes evident, and explains the fury of the fighting which took place there. The Battle in the Forest The Forest of Argonne consists of woods of beech, horn-beam, ash, and oak which, with an undergrowth of hazels and shrubs of many varieties, form almost impenetrable thickets. Lovely nooks and wild glens abound; opposite narrow ravines, whose steep sides are clothed with copse-wood, are cool valleys full of streams, pools, and springs.