The corps fought at the Battle of Jena on 14 October 1806 during the War of the Fourth Coalition. Ney's troops were engaged in the Siege of Magdeburg beginning on 22 October. General Franz Kasimir von Kleist surrendered on 11 November with 22,000 Prussian soldiers, 800 officers, 20 generals, and 700 artillery pieces. On 25 December, Marchand, with 6,000 men and 12 guns, defeated 3,000 Prussians at the Battle of Soldau. The corps arrived at 7:15 PM on 8 February 1807 at the Battle of Eylau. Ney's 17,000 men held off 63,000 Russians in a brilliant rear guard action in the Battle of Guttstadt-Deppen on 5 and 6 June. The corps led the successful counterattack at the Battle of Friedland on 14 June 1807.