qnli question: On which date did the battle begin with the Army of Chalons attacking various Prussian divisions? sentence: On 1 September 1870, the battle opened with the Army of Châlons, with 202 infantry battalions, 80 cavalry squadrons and 564 guns, attacking the surrounding Prussian Third and Meuse Armies totaling 222 infantry battalions, 186 cavalry squadrons and 774 guns.