Davout added to his renown in the battles of Eylau and Friedland. Napoleon left him as governor-general of the newly created Duchy of Warsaw following the Treaties of Tilsit in 1807, and the next year awarded him with the title of Duke of Auerstädt. During the War of the Fifth Coalition in 1809, Davout took part in the Battle of Eckmühl, and also distinguished himself in the Battle of Wagram, where he commanded the right wing. He was later made Prince of Eckmühl following the campaign. Davout was entrusted by Napoleon with the task of organizing the "corps of observation of the Elbe", which would become the gigantic army with which Napoleon invaded Russia in 1812. In this, he commanded the I Corps, numbering over 70,000, and defeated the Russians at Mohilev before he joined the main army, with which he continued throughout the campaign and the retreat from Moscow. During the retreat he conducted the rear guard, which was deemed too slow by the emperor, and was replaced by Marshal Michel Ney. His inability to hold out at Krasny until the arrival of Ney and his corps led him into disgrace and he would not meet with the emperor again until his return from Elba.