This first army, which was under the orders of General Dubail, was intrusted with the mission of making a vigorous attack and of holding in front of it the greatest possible number of German forces. The general in command of this army had under his orders, if the detachment from Alsace be included, five army corps and a division of cavalry. His orders were to seek battle along the line Saarburg-Donon, in the Bruche Valley, at the same time possessing himself of the crests of the Vosges as well as the mountain passes. These operations were to have as their theaters: (1) the Vosges Mountains, (2) the plateau of Lorraine to the northwest of Donon, and (3) the left bank of the Meurthe. This left bank of the Meurthe is separated from the valley of the Moselle by a bristling slope of firs, which is traversed by a series of passages, the defiles of Chipotte, of the Croix Idoux, of the Haut Jacques d'Anozel, of Vanemont, of Plafond. In these passes, when the French returned to the offensive in September, 1914, furious combats took place. The German forces opposed to this first army consisted of five active army corps and a reserve corps. The first French army, after a violent struggle, conquered the passes of the Vosges, but the conquest was vigorously opposed and took more time than the French had reckoned on. As soon as it had become master of the Donon and the passes, the first French army pushed forward into the defile of Saarburg. At St. Blaise it won the first German colors, took Blamont and Cirey (August 15, 1914), seized the defiles north of the canal of the Marne and the Rhine, and reached Saarburg. Here a connection was established with the army of Lorraine, which had commenced its operations on the 14th. A violent battle ensued, known under the name of the Battle of Saarburg. The left wing of the French army attacked August 19, 1914; it hurled itself at the fortified positions, which were copiously fringed with heavy artillery. In spite of the opposition it made progress to the northwest of Saarburg. On the 20th the attack was renewed, but from the beginning it was evident that it could not succeed and that the duty intrusted to the Eighth Army Corps of opening up the way for the cavalry corps could not be accomplished. This army corps had gone through a trying ordeal as a result of the bombardment by the heavy German artillery established in fortified positions, covering distances all measured in advance, with every group and French battery presenting a sure target and the action of the French cannon rendered useless.