The VI Corps was reconstituted for the invasion of Russia and placed under the command of General Laurent de Gouvion Saint-Cyr. The corps was composed entirely of Bavarian soldiers. At the First Battle of Polotsk on 16 to 18 August 1812, the Bavarians and the French II Corps together suffered 6,000 casualties, including Bavarian Generals Bernhard Erasmus von Deroy and Siebein killed, and Vincenti and Raglowitsch wounded. Saint-Cyr won his marshal's baton for this costly victory. The corps fought in the Second Battle of Polotsk on 18 to 20 October. This time, the combined Bavarian and French forces sustained 8,000 to 9,000 casualties before withdrawing to the southwest. A body of 2,100 surviving Bavarians was captured at Thorn on 16 April 1813 after a two-month siege.