With the arrival of the Emperor, who brought significant reinforcements, Grouchy received orders to incessantly harass the enemy, in order to prevent Bennigsen from reinforcing his left wing, and also to try and silence the enemy guns that had started to pound the French left.
With the arrival of the Emperor, who brought significant reinforcements, time was right for a general counterattack. Orders also required Grouchy to try and silence the enemy guns that had started to pound the French left.