After his consecutive defeats, Field-marshal Blücher decided to disengage from Napoleon and move a significant force against the isolated French Army Corps of Marshal Marmont, at Étoges. Blücher knew that Marmont's Corps was weak and his plan was to destroy it and thus fall upon the rear of Napoleon's main force. Still in pursuit of the debris of the enemy force, late on 13 February, Napoleon received reports that Marmont's Corps had been attacked and pushed out of his position at Étoges. The Emperor deduced that the enemy force before him would have to be a much reduced one and promptly decided to go to Marmont's aid. The Emperor left Château-Thierry on 14 February, towards 3 o'clock in the morning, leaving a small portion of his forces with Marshal Édouard Mortier, duc de Trévise, with orders to continue the pursuit of the enemy. Taking with him the cavalry of the Guard and Grouchy's Cavalry Reserve, Napoleon headed for the village of Vauchamps. Meanwhile, late on 13 February, having successfully regrouped what forces he could muster at Bergères-lès-Vertus, Blücher had launched an attack against Marmont's single division, pushing him out of Étoges and advancing as planned towards Champaubert and Fromentières, in the rear of Napoleon's force. However, having read Blücher's intentions, Napoleon had given orders for a concentration of French forces in that very sector. During the battle of Vauchamps on 14 February, Prussian Field-Marshal Blücher, commander of combined Prussian-Russian Army of Silesia could count on 20,000 to 21,500 men, from three Army Corps:   Kleist's II Corps numbered 13,500 men while Kaptzevich's X Corps counted 6,500 soldiers. There were also the 1,500 troops from IX Corps who survived the Battle of Champaubert. These were grouped into three or four temporary battalions and an artillery battery. The rump of IX Corps lost 600 men and all of its guns on the evening of 14 February. The II Corps had eight 6-pound batteries and two 12-pound batteries. Each battery had eight guns or a total of 80 cannons. There was also a howitzer battery of unknown strength. The X Corps had three batteries attached. Napoleon had sent orders for a major concentration of forces, which resulted in a force of some 25,000 men being assembled in this sector.