that the military conduct of the war should exclusively be the responsibility of the Commander-in-Chief. On 2 August, as small parties of German soldiers crossed the French border, Messimy told Joffre that he had the freedom to order French troops across the German but not the Belgian frontier. Joffre sent warning orders to the covering forces near the frontier, requiring the VII Corps to prepare to advance towards Mühlhausen (Mulhouse) to the north-east of Belfort and XX Corps to make ready to begin an offensive towards Nancy. As soon as news arrived that German troops had entered Luxembourg, the Fourth Army was ordered to move between the Third and Fifth armies, ready to attack to the north of Verdun. Operations into Belgium were forbidden, to deny the Germans a pretext until 4 August, when it was certain that German troops had already violated the Belgian border. To comply with the Franco-Russian Alliance, Joffre ordered an invasion of Alsace-Lorraine for 14 August, although anticipating a German offensive through Belgium. On 8 August, General Instruction No. 1 had ordered the Fifth Army to take a position on the left of the Fourth Army, ready to attack the southern flank of German force advancing from Mézières and Mouzon, through the difficult terrain in between. All four corps covered this front until 12 August, when Joffre allowed General Charles Lanrezac to move I Corps north to Givet to oppose a potential German attempt to cross the Meuse between Givet and Namur further north, which extended the army front to . As Lanrezac became aware of the size of the German force in Belgium and wanted to reinforce the left flank by moving to Namur, Joffre refused to allow the army front to be extended to and ordered Lanrezac to keep the army in a central position near Mézières, ready to oppose a German offensive from Mouzon to Namur. On 14 August Joffre and Lanrezac met but Joffre considered that only a few German cavalry and infantry parties had crossed the Meuse. With the BEF moving to Maubeuge and Hirson a redeployment of the Fifth Army would disrupt the deployment of the other armies. On 14 August a new intelligence report showed eight German corps between Luxembourg and Liège and by the next day Joffre allowed the move of the Fifth Army north, to operate beyond the Meuse. The XI Corps was transferred to the