If the left wing of the First Army found itself checked, the center and the right on the other hand were in an excellent position and were able to advance. But at this point (August 21, 1914) the Second French Army (the army of Lorraine) met a serious reverse in the region of Morhange and was compelled to retreat. This retreat left the flank of the First Army gravely unprotected, and as a consequence this army was also obliged to fall back. This rear-guard movement was accomplished over a very difficult piece of country down to the Baccarat-Ban de Sapt-Provenchere line, south of the Col du Bonhomme. It was found necessary to abandon the Donon and the Col de Sapt. The task committed to the Second Army, that of Lorraine under De Castlenau, was to protect Nancy, then to transfer itself to the east, advancing later to the north and attacking in a line parallel to that taken by the First Army on the Dieuze-Chateau Salins front in the general direction of Saarbruecken. Its mission was therefore at once both offensive and defensive: to cover Nancy and continue toward the west the attack of the First Army. After having repulsed, August 10 and 11, 1914, the strong German attacks in the region of Spincourt and of Chateau Salins the Second Army took the offensive and went forward almost without stopping during four days of uninterrupted fighting. Penetrating into Lorraine, which had been annexed, it reached the right bank of the Selle, cut off Marsal and Chateau Salins, and pushed forward in the direction of Morhange. The enemy fell back; at Marsal he even left behind enormous quantities of ammunition. As a matter of fact, he fell back on positions that had been carefully fortified in advance and whence his artillery could bombard at an almost perfectly accurate range. August 20, 1914, made a violent counterattack on the canal of Salines and Morhange in the Lake district. The immediate vicinity of Metz furnished the German army with a vast quantity of heavy artillery, which played a decisive role in the Battle of Morhange. The French retreated, and during this rear-guard movement the frontier city of Luneville was for some days occupied by the Germans. Thus the First and Second Armies failed in their offensive and saw themselves obliged to retreat, but their retreat was accomplished under excellent circumstances, and the troops, after a couple of days of rest, found themselves in a condition again to take the offensive. The First Army gave energetic support to the Second Army, which was violently attacked by the Germans in the second week of August. The German attack, which was first arrayed against Nancy, turned more and more to the east.