Despite these changes French armies still relied on plunder for a majority of their needs while on the move. Magazines were created for specific campaigns and any surplus was immediately sold for both monetary gain and to lessen the tax burden. The vehicles used to form convoys were contracted out from commercial interests or requisitioned from local stockpiles. In addition, given warfare of this era's focus on fortified towns and an inability to establish front lines or exert a stabilizing control over large areas, these convoys often needed armies of their own to provide escort[disambiguation needed]. The primary benefits of these reforms was to supply an army during a siege. This was borne out in the successful campaign of 1658 when the French army at no point was forced to end a siege on account of supplies, including the Siege of Dunkirk.[6]