Editing Battle of Eylau (section)

==Background==
With the Prussian army routed at Jena-Auerstedt, Napoleon occupied the major cities of Germany and marched east in pursuit of the remaining forces opposed to him. These were largely Russians under the command of the frail 68-year-old [[Field Marshal]] Count [[Mikhail Kamensky]]. The old marshal was unwilling to risk battle and continued to retreat, leaving the {{lang|fr|Grande Armée}} free to enter [[Poland]] almost unopposed. Nevertheless, as the French pressed aggressively eastward across the [[Vistula]], they found the Russians defending the line of the [[Wkra]] River. The French seized a crossing over the Wkra on 23 December at the [[Battle of Czarnowo]]. Russian resistance soon stiffened, and on 26 December, the two armies clashed at the [[Battle of Pułtusk|Battles of Pułtusk]] and [[Battle of Gołymin|of Gołymin]]. After the fierce engagements, Napoleon's troops took up winter quarters in Poland to recuperate after a victorious but exhausting campaign.

[[Image:Eylau Campaign Map 1807.JPG|thumb|left|upright=1.8|alt=Eylau Campaign Map 1807|The Eylau campaign map shows movements up to the Battle of Mohrungen on 25 January. German names are used for East Prussian towns. See text for Polish names.]]

In January 1807, the new Russian army commander, [[Levin August von Bennigsen]], attempted to surprise the French left wing by shifting the bulk of his army north from [[Nowogród]] to [[East Prussia]]. Incorporating a Prussian corps on his right, he first bumped into elements of the VI Corps of Marshal [[Michel Ney]], who had disobeyed his emperor's orders and advanced far north of his assigned winter cantonments. Having cleared Ney's troops out of the way, the Russians rolled down on the isolated French I Corps under Marshal [[Jean-Baptiste Bernadotte]]. Tough fighting at the [[Battle of Mohrungen]] allowed Bernadotte's corps to escape serious damage and pull back to the southwest. With his customary inventiveness, Napoleon saw an opportunity to turn the situation to his own advantage. He instructed Bernadotte to withdraw before Bennigsen's forces and ordered the balance of the {{lang|fr|Grande Armée}} to strike northward. That maneuver might envelop the Russian army's left flank and cut off its retreat to the east. By a stroke of luck, a band of [[Cossacks]] captured a messenger carrying Napoleon's plans to Bernadotte and quickly forwarded the information to General [[Pyotr Bagration]]. Bernadotte was left unaware, and a forewarned Bennigsen immediately ordered a retreat east to [[Jonkowo]] to avoid the trap.

As Bennigsen hurriedly assembled his army at Jonkowo, elements of Marshal [[Nicolas Soult]]'s [[IV Corps (Grande Armée)|IV Corps]] reached a position on his left rear on 3 February.{{sfn|Petre|1976|pp=150–151}} That day, General of Division [[Jean François Leval]] clashed with Lieutenant-General [[Nikolay Kamensky]]'s 14th Division at Bergfried (Berkweda) on the [[Łyna (river)|Alle (Łyna) River]], which flows roughly northward in the area. The French reported 306 casualties but claimed to have inflicted 1,100 on their adversaries.{{sfn|Smith|1998|p=240}} After seizing [[Olsztyn|Allenstein (Olsztyn)]], Soult moved north on the east bank of the Alle. Meanwhile, Napoleon threatened Bennigsen from the south with Marshal [[Pierre Augereau]]'s VII Corps and Ney's forces. Kamensky held the west bank with four Russian battalions and three Prussian artillery batteries.{{sfn|Petre|1976|pp=150–151}} After an initial attack on Bergfried had been driven back, the French captured the village and bridge. A Russian counterattack briefly recaptured the bridge. That night, the French remained in possession of the field, and Soult claimed that he had found 800 Russian dead there.{{sfn|Petre|1976|p=152}} Marching at night, Bennigsen retreated directly north to [[Wilczkowo, Warmian-Masurian Voivodeship|Wolfsdorf (Wilczowo)]] on the 4th. The next day, he fell back to the northeast, reaching Burgerswalde on the road to [[Górowo Iławeckie|Landsberg (Górowo Iławeckie)]].{{sfn|Petre|1976|p=154–155}}

By early February, the Russian army was in full retreat and was relentlessly pursued by the French. After several aborted attempts to stand and fight, Bennigsen resolved to retreat to the town of Preussisch-Eylau and there make a stand. During the pursuit, perhaps influenced by the dreadful state of the Polish roads, the savage winter weather and the relative ease with which his forces had dealt with Prussia, Napoleon had allowed the {{lang|fr|Grande Armée}} to become more spread out than was his custom. In contrast, Bennigsen's forces were already concentrated.