The VIII Corps was involved in the unsuccessful Siege of Kolberg from 20 March to 2 July 1807. Mortier's 14,000 men and 41 guns included the Fusilier-Chasseurs and Fusilier-Grenadiers of the Imperial Guard under Savary, Loison's French division of six infantry battalions and nine cavalry squadrons, General Charles Louis Dieudonné Grandjean's Dutch contingent with 12 battalions and two hussar regiments, six Italian battalions with supporting cavalry, two Polish battalions, and seven German battalions. The VIII Corps lost 5,000 killed, wounded, or died of illness. The defenders of the 230-gun Kolberg fortress lost 3,000 of the 6,000-man garrison killed, wounded, or died of disease. In June, however, Mortier was called to join the main army. He led 8,465 foot soldiers and 1,200 horsemen in the thick of the action at the Battle of Friedland on 14 June 1807. General Pierre-Louis Dupas led the all-French 1st Division, General Jean Henri Dombrowski commanded the all-Polish 2nd Division, and General Maurice Ignace Fresia directed the Dutch and Polish cavalry contingent.