After its victory over Napoleon at La Rothière on 1 February 1814 the Coalition decided that Prince Gebhardt von Blücher’s Army of Silesia and Prince Karl Philipp zu Schwarzenberg’s Army of Bohemia should advance on Paris by separate routes. Blücher would move along the Marne through Châlons and Meaux. Schwarzenberg was to advance beside the Seine through Troyes. Prince Piotr Wittgenstein’s corps and Alexander Seslavin’s Cossacks would link the two armies.
F. Lorraine Petre says that Schwarzenberg devised this strategy because he thought that keeping the two armies together would create major supply problems, whilst the more aggressive Blücher agreed because he was happy to operate independently.
David Chandler notes that Schwarzenberg ‘for political reasons was secretly not so keen to see Napoleon’s immediate downfall.’ The Austrian Chancellor Prince Klemens von Metternich was concerned that the overthrow of Napoleon would boost German nationalism, which he feared would weaken Austria’s position in central Europe. Peace negotiations at Châtillon-sur-Seine began on 3 February.
Click here for a campaign map from West Point’s website.
The division of the two Coalition armies gave Napoleon an opportunity to attack and defeat one of them; his army was too small to take on the two combined. His original plan was to attack Schwarzenberg with 40,000 men. He thought that Blücher was heading for Nogent, where the Emperor expected to have 21,000 infantry, 2,400 cavalry and 46 guns by 6 February, enough to hold off Blücher.
However, Blücher was headed for Paris, and he was moving more quickly than the cautious Schwarzenberg. Schwarzenberg, concerned by the threat to his flanks, moved Wittgenstein and Seslavin’s forces closer to his own, widening the gap between the two Coalition armies. Blücher’s army had also become over-extended because of the speed of its advance.
On 6 February Napoleon learnt of the threat to Paris, but thanks to interior lines was able to move his army to face Blücher. On the same day, however, he received several pieces of bad news: a Prussian corps under General Friederich von Bülow had taken Brussels and cut off Antwerp; Blücher’s advance had created great alarm in Paris; Napoleon’s brother-in-law Joachim Murat, the King of Naples, had defected; and the peace talks were going badly.
The Coalition was prepared to allow Napoleon to remain Emperor of France, but only within its 1792 frontiers. After a day’s consideration he decided that he was not prepared to accept less than France’s natural frontiers, which he argued stretched to the Rhine.
Napoleon’s immediate problem was that he did not know Blücher’s dispositions. In fact, the main column of the Army of Silesia was spread over 44 miles on 8 February, with General Johan-David-Ludwig Yorck’s corps 10-12 miles to the north. Napoleon was informed on 9 February that the 15,000 men of Prince Fabian von Osten-Sacken’s corps were at Montmirail.
In total Napoleon had about 70,000 men facing 200,000. His need to cover the advance of two enemy armies meant that he had to divide his force into three parts. However, he believed that he could concentrate a field army of 30,000 men against Blücher’s force of about 45,000, 5,000 of whom were tied up by Marshal Jacques Macdonald’s corps.
On 9 February the French army moved north through Sézanne towards Champaubert. The same day Blücher ordered 30,000 of his troops to march on Sézanne the next day, However, on learning of Napoleon’s move Blücher decided instead to conduct an enveloping manoeuvre to Sézanne via La-Fère-Champenoise. His new orders were slow to reach some of subordinates, and his army remained scattered.
On 10 February Napoleon’s army encountered a small force commanded by Count Zakhar Olsufiev at Champaubert. Olsufiev had at most 4,000 infantry, 24 guns and few cavalry. He might have retreated, but he had been criticised by Sacken for withdrawing at Brienne on 29 January. He therefore stood his ground against a vastly superior force.
When Olsufiev did eventually try to withdraw his retreat was hampered by bad weather and poor roads. Only 1600-1700 of his men and 15 of his guns escaped. Olsufiev himself was captured. French casualties were only about 200 dead and wounded. Dominic Lieven notes that Napoleon claimed to have taken 6,000 prisoners, more than Olsufiev’s total force. Ralph Ashby notes that fighting at home gave Napoleon an advantage, with peasants turning out to help move his guns through the mud.
 F. L. Petre, Napoleon at Bay 1814 (London: John Lane, The Bodley Head, 1914), p. 99.
 D. Chandler, The Campaigns of Napoleon (London: Weidenfeld & Nicolson, 1966), pp. 964-65.
 Unless otherwise stated troop strengths are from Ibid., pp. 966-71.
 Petre, Napoleon at Bay 1814, p. 55.
 D. C. B. Lieven, Russia against Napoleon: The Battle for Europe, 1807 to 1814 (London: Penguin, 2010). pp. 486-87 says 3,690 infantry and 17 cavalry; Petre, Napoleon at Bay 1814. p. 58-59 says 4,000 infantry, 24 guns and no cavalry, but notes that a Russian source says 3,690 infantry.
 Chandler, Campaigns, p. 969; Petre, Napoleon at Bay 1814, p. 60.
 Lieven, Russia, p. 487.
 R. Ashby, Napoleon against Great Odds: The Emperor and the Defenders of France, 1814 (Santa Barbara, CA: Praeger, 2010).