Napoleon, after several months of recuperating from Eylau, orders the Grande Armée on the move once again.

Learning that the Russians have encamped at their operational base in the town of Heilsberg, by the Alle River, Napoleon decides to conduct a general assault in the hopes of dislodging what he thinks is the rearguard of the Russian army.

In fact, the French run into the entire Russian army of over fifty thousand men and one hundred and fifty artillery guns.

Repeated and determined attacks by the French fail to dislocate the Russians, who are fighting inside elaborate earthworks designed to prevent precisely the kind of river crossing Napoleon is attempting.

French casualties soar to ten thousand while the Russians lose about six thousand.

The Russians eventually withdraw from Heilsberg as their position becomes untenable, prompting Napoleon to chase after them once again.

The French head in the direction of Königsberg to gain additional supplies and provisions.