"Cavalry is useful before, during and after the battle," wrote Napoleon, and he stressed the need for audacity in its employment and careful training to achieve true discipline. He was also insistent that careful categorization according to role was of great importance... It was some time before the French cavalry reached its full potential, as it had suffered the loss of many officers during the Revolutionary period, but by 1807 it was reaching its prime. The great charges led by Murat at Eylau and Grouchy at Friedland played vital parts in the outcome of these battles.