Napoleon and the French obtained a decisive victory that routed much of the Russian army, which retreated chaotically over the Alle river by the end of the fighting.

[13] Lannes skillfully held his ground against determined Russian attacks until Napoleon could bring additional forces onto the field.

Friedland effectively ended the War of the Fourth Coalition, as Emperor Alexander I reluctantly entered peace negotiations with Napoleon.

These discussions eventually culminated in the Treaties of Tilsit, by which Russia agreed to join the Continental System against Great Britain and by which Prussia lost almost half of its territories.

Some historians regard the political settlements at Tilsit as the height of Napoleon's empire because there was no longer any continental power challenging the French domination of Europe.

Following the French victory at the Battle of Austerlitz in December 1805, Prussia went to war in 1806 to recover her position as the leading power of Central Europe.

Napoleon ordered a raid to seize a subversive, anti-Napoleonic bookseller named Johann Philipp Palm in August 1806, and made a final attempt to secure terms with Britain by offering her Hanover, which infuriated Prussia.

[18] 180,000 French troops began to cross the Franconian forest on 2 October 1806, deployed in a bataillon-carré (square-battalion) system designed to meet threats from any possible direction.

[22] The Russian general Bennigsen worried that French forces might cut him off from Buxhoevden's army, so he abandoned Warsaw and retreated to the right bank of the Vistula.

Bennigsen noticed a good opportunity to strike at an isolated French corps, but he abandoned his plans once he realized Napoléon's maneuvers intended to trap his army.

[24][25] Napoleon hoped to pin Bennigsen's army long enough to allow Ney's and Davout's troops to outflank the Russians.

The French found themselves in dire straits until a massed cavalry charge, made by 10,700 troopers formed in 80 squadrons,[26] relieved the pressure on the centre.

[28] Repeated and determined attacks by the French failed to dislocate the Russians, who were fighting inside elaborate earthworks designed to prevent precisely the kind of river crossing Napoleon was attempting.

Crucially, Bennigsen believed he had enough time to cross the Alle the following day, to destroy the isolated units of Lannes, and to withdraw back across the river without ever encountering the main French army.

Bennigsen's main body began to occupy the town on the night of 13 June, after Russian forces under General Golitsyn had driven off the French cavalry outposts.

Knowing that Napoleon was within supporting distance with at least three corps, Lannes sent aides galloping off with messages for help and waged an expert delaying action to fix Bennigsen in place.

Both sides now used their cavalry freely to cover the formation of lines of battle, and a race between the rival squadrons for the possession of Heinrichsdorf ended in favor of the French under Grouchy and Nansouty.

Having thrown all of his pontoon bridges at or near the bottleneck of the village of Friedland, Bennigsen had unwittingly trapped his troops on the west bank.

Napoleon feared that the Russians meant to evade him again, but by 6 am Bennigsen had nearly 50,000 men across the river and forming up west of Friedland.

The main attack was to be delivered against the Russian left, which Napoleon saw at once to be cramped in the narrow tongue of land between the river and the Posthenen mill-stream.

Ney's attack indeed came eventually to a standstill; Bennigsen's reserve cavalry charged with great effect and drove him back in disorder.

As at Eylau, the approach of night seemed to preclude a decisive success, but in June and on firm ground the old mobility of the French reasserted its value.

Napoleon assured the envoy that the Vistula River represented the natural borders between French and Russian influence in Europe.

Given the victory he had just achieved, the French emperor offered the Russians relatively lenient terms–demanding that Russia join the Continental System, withdraw its forces from Wallachia and Moldavia, and hand over the Ionian Islands to France.

Moreover, Alexander's pretensions at friendship with Napoleon led the latter to seriously misjudge the true intentions of his Russian counterpart, who would violate numerous provisions of the treaty in the next few years.