The leading elements of the Austrian attack ran into Montbrun's determined cavalry, who managed to reduce the impetus of the charge thanks to hilly and wooded terrain. Rosenberg displayed serious concern when he realized that Davout's troops were not moving to account for the ongoing battle, and rightly assumed that more French troops were on the way. These troops had, in fact, arrived and brushed aside Rosenberg's flank guard. Napoleon had set the French army into motion around 2 a.m. on the 22nd and had his men march 18 miles north in just a few short hours, meaning reinforcements for Davout would be arriving faster than promised.