▁ ▁Despite ▁the ▁four ▁divisions ▁of ▁the ▁II ▁Caval ry ▁Corps ▁( General ▁Georg ▁von ▁der ▁Mar witz ), ▁the ▁Germ ans ▁were ▁pushed ▁back ▁to ▁a ▁line ▁from ▁Rib éc ourt ▁to ▁L assign y ▁and ▁Ro ye , ▁which ▁men ac ed ▁German ▁communic ations ▁through ▁Ham ▁and ▁St . ▁Qu entin . ▁On ▁ 2 4 ▁September , ▁the ▁French ▁were ▁attacked ▁by ▁the ▁XVIII ▁Corps ▁as ▁it ▁arrived ▁from ▁Re ims , ▁which ▁forced ▁back ▁the ▁French ▁IV ▁Corps ▁at ▁Ro ye ▁on ▁the ▁right ▁fl ank . ▁To ▁the ▁north , ▁the ▁French ▁reached ▁P ér onne ▁and ▁formed ▁a ▁bridge head ▁on ▁the ▁east ▁bank ▁of ▁the ▁Som me , ▁only ▁for ▁the ▁German ▁XIV ▁Reserve ▁Corps ▁to ▁reach ▁B apa ume ▁to ▁the ▁north ▁on ▁ 2 6 ▁September . ▁The ▁off ensive ▁capacity ▁of ▁the ▁Second ▁Army ▁was ▁exha usted ▁and ▁def ensive ▁positions ▁were ▁occupied , ▁while ▁J off re ▁sent ▁four ▁more ▁corps ▁to ▁rein force . ▁Over ▁the ▁next ▁week , ▁the ▁northern ▁fl ank ▁of ▁the ▁Second ▁Army ▁moved ▁further ▁north ▁and ▁on ▁ 2 9 ▁September , ▁a ▁ ▁( General ▁Louis ▁de ▁Ma ud ' hu y ) ▁was ▁formed , ▁to ▁control ▁the ▁northern ▁corps ▁of ▁the ▁Second ▁Army ▁as ▁they ▁assemble d ▁near ▁Ar ras . ▁ ▁Battle ▁of ▁Albert , ▁ 2 5 – 2 9 ▁September ▁ ▁On ▁ 2 1 ▁September , ▁Fal ken h ay n ▁decided ▁to ▁concent rate ▁the ▁ 6