When operating in enemy territory an army was forced to plunder the local countryside for supplies, a historical tradition meant to allow war to be conducted at the enemy's expense. However with the increase in army sizes this reliance on plunder became a major problem, as many decisions regarding where an army could move or fight were made based not on strategic objectives but whether a given area was capable of supporting the soldiers' needs. Sieges in particular were affected by this, both for any army attempting to lay siege to a location or coming to its relief. Unless a military commander was able to implement some sort of regular resupply a fortress or town with a devastated countryside could be effectively immune to either operation.