The advance guard of Marshal Lannes reports seeing large numbers of Russian troops at the town of Friedland on June 13.

Both sides engage one another for the remainder of the day with no result.

Crucially, Bennigsen believes he has 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 begins to occupy the town on the night of June 13, after Russian forces under General Golitsyn have driven off the French cavalry outposts.

The army of Napoleon marches on Friedland, but remains dispersed on its various march routes, and the first stage of the engagement becomes a purely improvisational battle.

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

With never more than twenty-six thousand men, Lannes forces Bennigsen to commit progressively more troops across the Alle to defeat him.