However, the Guard cavalry was not needed as a whole before the epic "Battle of Nations" at Leipzig. Placed in reserve at first, the Guard cavalry and artillery had to spring into action at once, after Napoleon received news of the Saxon defection. With the Saxons now in the Coalition camp and firing at the soldiers who moments before had been their allies, the situation of some of the French troops became desperate. The position of General Durutte's division, placed close to Saxon lines, was particularly tenuous and Napoleon soon came to its aid, with Nansouty in command of the Guard cavalry and horse artillery. Nansouty launched an impetuous charge with some of his regiments, the "Grenadiers-à-cheval", "Dragons" and "Chevau-légers" and the Saxons were unable to hold out in this sector. However, the situation changed on 19 October, with the untimely explosion of a bridge over the Elster, the main retreat line for the French rearguard, which was now blocked in the city of Leipzig. The Guard cavalry extricated itself from the field of battle and was very useful in covering the retreat of the remaining French forces.