▁the ▁ground . ▁By ▁ 2 0 ▁August ▁a ▁German ▁counter - off ensive ▁in ▁Lor raine ▁had ▁begun ▁and ▁the ▁German ▁ 4 th ▁Army ▁and ▁ 5 th ▁Army ▁advanced ▁through ▁the ▁Ar den nes ▁on ▁ 1 9 ▁August ▁towards ▁Ne uf ch âteau . ▁An ▁off ensive ▁by ▁French ▁Third ▁and ▁Four th ▁Arm ies ▁through ▁the ▁Ar den nes ▁began ▁on ▁ 2 0 ▁August , ▁in ▁support ▁of ▁the ▁French ▁invasion ▁of ▁Lor raine . ▁The ▁oppos ing ▁arm ies ▁met ▁in ▁thick ▁fog ▁and ▁the ▁French ▁mist ook ▁the ▁German ▁troops ▁for ▁screen ing ▁forces . ▁On ▁ 2 2 ▁August ▁the ▁Battle ▁of ▁the ▁Ar den nes ▁ ▁began ▁with ▁French ▁attacks , ▁which ▁were ▁cost ly ▁to ▁both ▁sides ▁and ▁forced ▁the ▁French ▁into ▁a ▁dis order ly ▁retre at ▁late ▁on ▁ 2 3 ▁August . ▁The ▁Third ▁Army ▁re co iled ▁towards ▁Verd un , ▁purs ued ▁by ▁the ▁ 5 th ▁Army ▁and ▁the ▁Four th ▁Army ▁retre ated ▁to ▁Sed an ▁and ▁St en ay . ▁Mul house ▁was ▁re capt ured ▁again ▁by ▁German ▁forces ▁and ▁the ▁Battle ▁of ▁the ▁Me use ▁ ▁caused ▁a ▁temporary ▁halt ▁of ▁the ▁German ▁advance . ▁ ▁Li ège ▁was ▁occupied ▁by ▁the ▁Germ ans ▁on ▁ 7 ▁August , ▁the ▁first ▁units ▁of ▁the ▁BE F ▁land ed ▁in ▁France ▁and ▁French ▁troops ▁crossed ▁the ▁German ▁front ier . ▁On ▁ 1 2 ▁August ▁the ▁Battle ▁of ▁H ael en ▁was ▁fought