Schwarzenberg's 100,000-strong army defeated Napoleon's 30,000 troops at the Battle of Arcis-sur-Aube on 20–21 March 1814. Napoleon attacked the Allies before MacDonald's troops all joined him and sent orders to that marshal to hurry up. When the Allies forced the French to retreat on the evening of the 21st, MacDonald's two lead divisions just arrived and Amey's division was well to the west at Anglure. MacDonald's troops formed the rearguard of Napoleon's army as it retreated to the northeast toward Vitry-le-François. On the 23 March, an ambiguously-written order sent Amey's troops to Sézanne, leaving the unguarded artillery park to attacked by the Russian Guard light cavalry. Another French unit rescued part of the convoy but 15 artillery pieces and 300 prisoners were carried off. At this time, Marshals Auguste de Marmont and Édouard Mortier, duc de Trévise were following Napoleon's orders to move east toward Vitry. The evening of 23 March found the two marshals at Vertus and Étoges. At Sézanne, Amey's 1,800 men found Michel-Marie Pacthod's 4,000-man division and a food convoy with 80 wagons. Hearing that a French corps was nearby, Pacthod and Amey decided to join forces with it. Their force reached Étoges on the evening of 24 March and sent messengers to Marmont and Mortier requesting instructions.