The march losses suffered by N`s central section of the Grande Armee in Russia in 1812 are well documented. Before fighting the battle of Smolensk, those corps had lost 50% of their strengths at the point when they crossed the River Niemen a few weeks before and clashes with the enemy up to that point had been very minor.
Losses were caused by the great heat, the forced paces of the marches and a total breakdown of the supply system.