were ordered to end their attacks and dig in. The withdrawal was intended to make time for the 7th Army to be transferred from Alsace, to the right wing near the Oise but Franco-British attacks led to the 7th Army being sent to fill the gap between the 1st and 2nd armies instead. Moltke was replaced by Falkenhayn on 14 September, by when the 1st Army had reached the Aisne, with its right flank on the Oise and the 7th Army had assembled on the Aisne, between the 1st and 2nd armies. Further east the 3rd, 4th and 5th armies had dug in from Prosnes to Verdun, secure from frontal attacks. The 1st Army was still vulnerable on its northern flank, to attacks by French troops transferred from the south, which could be moved faster over undamaged railways, than German troops using lines damaged during the Great Retreat. General Wilhelm Groener, head of the Railway Department of the OHL, suggested three alternatives, a frontal attack from the new positions, a defence of the line of the Aisne while reserves were transferred to the right flank or to continue the withdrawal and comprehensively regroup the German armies, ready to conduct an offensive on the right flank. On 15 September, Falkenhayn wanted to continue the withdrawal and ordered the 1st Army to fall back and dig in from Artems to La Fère and Nouvion-et-Catillon, to protect the right flank from a French offensive, while the 6th Army moved from Lorraine to the western flank, ready for a general offensive to begin progressively on 18 September from the 5th Army in the east, pinning French troops down westwards, until the 6th Army enveloped the French, beyond the right of the 1st Army. The plan was cancelled soon afterwards, when (Colonel) Gerhard Tappen (OHL Operations Branch), reported from a tour of inspection at the front that the French were too exhausted to begin an offensive, that a final push would be decisive and that more withdrawals would compromise the morale of the German troops, after the defeat on the Marne. From Falkenhayn ordered the 1st, 2nd and 7th armies, temporarily under the command of General Karl von Bülow, to attack southwards and the to attack with the intention of weakening the French and preventing troops from being moved westwards. The 6th Army began to move to the western flank on 17 September, ready for