"Napoleon on the field of Eylau" by Antoine-Jean Gros

The Battle of Eylau or Battle of Preussisch-Eylau, 7 and 8 February 1807, was a bloody and inconclusive battle between Napoléon's Grande Armée and a Russian Empire army under Levin August, Count von Bennigsen near the town of Preußisch Eylau in East Prussia. Late in the battle, the Russians received a timely reinforcement from a Prussian division. The town is now called Bagrationovsk and it is a part of Kaliningrad Oblast, Russia. The engagement was fought during the War of the Fourth Coalition, part of the Napoleonic Wars. Of all Napoleonic battles, this is considered to be the most uncertain and mysterious for several reasons — mainly the strength of Murat's reserve cavalry.

• http://en.wikipedia.org/wiki/Battle of Eylau