This large size came at a cost, as the logistics of feeding a huge army made them especially dependent on supplies. Most armies of the day relied on the supply-convoy system established during the Thirty Years' War by Gustavus Adolphus. This limited mobility, since the soldiers had to wait for the convoys, but it did keep possibly mutinous troops from deserting, and thus helped preserve an army's composure. However, Napoleon's armies were so large that feeding them using the old method proved ineffective, and consequently, French troops were allowed to live off the land. Infused with new concepts of nation and service. Napoleon often attempted to wage decisive, quick campaigns so that he could allow his men to live off the land. The French army did use a convoy system, but it was stocked with very few days worth of food; Napoleon's troops were expected to march quickly, effect a decision on the battlefield, then disperse to feed. For the Russian campaign, the French did store 24 days' worth of food before beginning active operations, but this campaign was the exception, not the rule.
