The two Allied corps managed to escape across the Marne River, but suffered considerably heavier losses than the pursuing French.

This action occurred during the Six Days' Campaign, a series of victories that Napoleon won over Prussian Field Marshal Gebhard Leberecht von Blücher's Army of Silesia.

Blücher's troops marched northwest and followed the Marne valley in a thrust toward Paris while Schwarzenberg's army moved west through Troyes.

Leaving part of his badly outnumbered army to watch Schwarzenberg's slow advance, Napoleon moved north against Blücher.

Catching the Silesian Army badly strung out, Napoleon demolished Zakhar Dmitrievich Olsufiev's Russian corps in the Battle of Champaubert on 10 February.

Turning west, the French emperor defeated Sacken and Yorck in the hard-fought Battle of Montmirail on the following day.

As the Allies scrambled north toward Château-Thierry's bridge across the Marne, Napoleon launched his army in hot pursuit but failed to annihilate Yorck and Sacken.

The Russian corps of Peter Wittgenstein and a Cossack scouting force under Alexander Nikitich Seslavin would provide the link between the two armies.

Already on 4 February, Schwarzenberg started to become anxious about his left flank and began pulling Wittgenstein's corps to the south, away from Blücher.

[5] On 5 February, Russian General Michael Andreas Barclay de Tolly ordered Seslavin's force away to the extreme left flank without notifying Blücher.

Over the next few days, the Prussian field marshal mistakenly continued to believe that Seslavin watched the gap on his left flank.

[6] The French emperor calculated that Marshals Claude Perrin Victor and Nicolas Oudinot with 39,000 troops would be able to hold off the cautious Schwarzenberg.

On 9 February, with everyone marching west, Kaptzevich and Kleist reached Bergères-lès-Vertus, Olsufiev arrived at Champaubert, Sacken got to La Ferté-sous-Jouarre, and Yorck approached Château-Thierry.

Prussian staff officer Karl Freiherr von Muffling wrote that Sacken had 20,000 soldiers and Yorck's corps numbered 18,000 men while Olsufiev, Kaptzevich and Kleist together counted 19,000 troops.

Though Yorck urged his ally to retreat toward Château-Thierry, Sacken remained unaware of his danger and determined to fight what he believed was a weak enemy force.

In the event, MacDonald had broken the Trilport bridge over the Marne, preventing him from striking Sacken's corps from the west.

Delayed by the muddy roads, Yorck's tired troops were approaching Montmirail from the north, but still out of touch with Sacken.

Napoleon barely managed to interpose some French soldiers at an important road intersection between the two Allied corps.

[12] In the Battle of Montmirail, Napoleon with 10,500 men and 36 guns faced Sacken's 18,000 Russians at 11:00 am while the vanguard of Yorck's 18,000 Prussians appeared to the north.

Marshal Édouard Mortier commanded the pursuit on the main highway while Napoleon personally led another column farther west through Rozoy.

The position was attacked by two battalions of Old Guard Foot Chasseurs and Napoleon's duty squadrons led by Claude-Étienne Guyot.

Aware that he would have to fight with a river at his back, Yorck ordered his wagon train to cross to the north bank of the Marne.

Two battalions of Old Guard Foot Grenadiers and the duty squadrons pressed back the Prussian right flank under Prince William almost to Château-Thierry.

[24] Napoleon wrote, "My Foot and Horse Guard covered themselves with glory … The enemy seemed struck by a singular terror".

[24] Since 11 February, Marshal Auguste de Marmont with one infantry division and the I Cavalry Corps watched Blücher.