The detachment was an independent corps command under the control of Marshal Nicholas Oudinot and later reenforced by a corps of Bavarian troops under the command of Marshal Gouvion Saint-Cyr. The goal of this independent command was to guard the Grand Armee's left flank and push the Russian forces under the command of Count Peter von Wittgenstein towards Pskov. Although Oudinot initially outnumbered the Russian forces, von Wittgenstein was able outfox the French marshal, who was not the brightest light in the marshallate, and the Russian forces remained intact. This Grand Armee force was simultaneously both too big and too small for the task Napoleon had set for it. The army was not large enough to take on von Wittgenstein's reenforced troops and ran out of supplies. Saint-Cyr would claim during his memoirs that during the First Battle of Polotsk, one-quarter of the French troops were out foraging. The resulting battle was a costly French tactical victory, but one in which failed to push the Russian force away from Polotsk. But the remaining French force was too large for the Russians to wholly dislodge, leading to a stalemate of sorts where the French held their positions and suffered attrition and the Russians nipped away at their enemy. Although some French commanders applauded their bravery on the field, they also noted that the Bavarian contingent was quite deficient in preparing to acclimate to the Russian weather. This led to the high level of wastage, but not nearly to the extent of the main force of the Grande Armee, which had to march much longer in the Russian summer heat.

The fate of this corps was reflective of the many shortcomings Napoleon displayed during the 1812 campaign. None of Napoleon's marshals, save Davout, Massena, and at this point in the war, Suchet, worked well in unsupervised and independent commands. But Suchet was in Spain, Massena in semi-retirement, and Davout was needed in the main body. Napoleon also expected Russian resistance to be much smaller and more concentrated despite his prior experience fighting the Russian army at Eylau and Friedland. So neither Oudinot nor Saint-Cyr had much of an appreciation of what to do with their detachment nor did they possess enough troops to accomplish Napoleon's ambitious directives. Thus the whole Russian campaign became hostage to the fate of the main force led by the Emperor.

Sources

Hausmann, Franz Joseph, Cynthia Joy Hausmann, and John H. Gill. A Soldier for Napoleon: The Campaigns of Lieutenant Franz Joseph Hausmann, 7th Bavarian Infantry. London: Greenhill Books, 1998.

Lieven, D. C. B. Russia against Napoleon The True Story of the Campaigns of War and Peace. New York, N.Y.: Viking, 2010.