On July 23, 1812, the battle of Saltanovka took place after the French had captured the nearby town of Mogilev (about 250 miles east of the crossing of the Niemen river). This action prevented the Russian 2nd army under Bagration from joining up with the main Russian army under Michael Andreas Barclay de Tolly . The French were led by Marshal Davout.
At 7 am on the 23rd, the Russians advanced on the French front and also attempted to turn the French right. The battle lasted all day with 9,000 French fending off 20,000 Russians. The defeated Russians retreated east to Smolensk where they were able to join up with the main Russian army on August 4th. The joining of the two Russian armies set-up the conditions for the battle of Smolensk.