Lannes endeavoured to pierce the Russian left and cut them off from the town, but did not succeed in getting through, and in this part of the field the action was indecisive. On their left the French did little more than hold their own, but the Russians retired during the night, having lost 3,000 killed and wounded, 2,000 prisoners and a large number of guns. The French admitted a loss of only 1,500 although Russian accounts estimate French losses at about 8,000.
The twin battles of Jena and Auerstedt (older name: Auerstädt) were fought on October 14, 1806 on the plateau west of the river Saale in today's Germany, between the forces of Napoleon I of France and Frederick William III of Prussia.
Nevertheless, it was a fierce battle, and Napoleon mistakenly believed that he had faced the main body of the Prussian army.
Hegel considered this battle to be "the end of the history", in terms of evolution of human societies towards what we would call the "liberal democracy".
The Battle of Eylau, fought on 7-February 8, 1807, was a bloody and inconclusive contest between the forces of Napoléon and a mostly Russian army under General Bennigsen.
Kamensky was unwilling to risk battle, and continued to retreat, leaving the Grande Armée free to enter Poland almost unopposed.
Eylau was not the decisive victory characteristic of Napoleon's earlier campaigns, prolonging the war with Russia until the Battle of Friedland forced Czar Alexander I to the peace table.