On September 8, the Germans bombarded the Fort of Troyon. The Governor of Verdun telegraphed to the officer in command of the fort that victory depended upon his resistance, and requested him to hold out “indefinitely.” As a precautionary measure, General Sarrail ordered several of the bridges across the Meuse to be destroyed. On September 9, the fort’s guns were put out of action, but the defenders repulsed several assaults. Génicourt Fort was next bombarded. [Illustration: THE FIRST GERMAN ATTACKS AGAINST THE MEUSE HEIGHTS _While the Battle of the Marne was raging, the Germans attempted in vain to capture the Meuse Heights, in order to take Gen. Sarrail’s Army—the pivot of Joffre’s manoeuvre—in the rear._] On the 10th, the forts were still holding out, although deluged with shells. Meanwhile the German infantry advanced towards St. Mihiel. However, the Battle of the Marne had now been won on the left wing, and the German retreat, which was to extend as far as the Verdun—St. Mihiel district, had begun. General de Castelnau despatched the 73rd Reserve and 2nd Cavalry Divisions of his army to Troyon, and the fort was relieved on September 13. The mobile defence forces of Verdun pursued the retreating Germans across the Meuse and established themselves to the east of the town, while General Sarrail’s army advanced towards the north and west. The German plan had completely failed. [Illustration: THE FORMATION OF THE ST. MIHIEL SALIENT (_Sept. 20–29, 1914_)] Their set-back at Troyon did not prevent the Germans reforming, and they attacked the Meuse Heights again on September 20, in an endeavour to outflank Verdun from the south. Four army corps under General von Strantz, starting from Metz, advanced rapidly on the 22nd to the Combres-Vigneulles-Thiaumont line, and began a methodical bombardment of the forts on the Meuse Heights. These were soon pounded into shapeless heaps of _débris_, but the gallant defenders still held on and repulsed all assaults. On the 23rd, the enemy advanced to Seicheprey. The mobile defence forces of the region, greatly outnumbered (two or three to one), formed only a very thin line, the depth of which steadily decreased as it extended beyond Verdun to the south.