The corps was first called into existence during the War of the Third Coalition in 1805. After destroying much of the Austrian Empire's military strength in the Ulm campaign, Napoleon ordered his generals to advance toward the Austrian capital of Vienna. The emperor formed a new VIII Corps under Mortier and assigned four divisions to the new organization. Mortier's task was to operate on the north bank of the Danube and protect the French army's strategic left flank. The divisions were led by Generals Jean-Baptiste Dumonceau, Honoré Théodore Maxime Gazan de la Peyrière, Pierre Dupont de l'Etang, and Louis Klein. Dumonceau's division transferred from the II Corps, Gazan's from the V Corps, Dupont's from the VI Corps, and Klein's from the I Cavalry Corps. On 11 November 1805, Mortier with the 5,000 men of Gazan's division bumped into a greatly superior force of Russians and Austrians. In the Battle of Dürenstein, Gazan suffered 3,000 casualties but was saved from annihilation when Dupont's division arrived later in the day. Neither Klein nor Dumonceau were engaged in the action. The VIII Corps missed the Battle of Austerlitz.