The wars began not long after the loss of the Shield of Achille, as Daventry no longer had any magical defense to prevent Daventry from losing. Following the loss of the Gold Chest they could no longer pay their armies and mercenaries to stop invading forces.
By the end of the wars Daventry was left with only 100 knights and soldiers defending the kingdom, and the magical spells of wizards placed on the castle to defend it.
Graham was forced to defend from the invaders from outside countries, and even his father Hereward another of Daventry's greatest knights died during one of the border wars. Perhaps the knight, James of Daventry died during one of these wars (though he may have died long before Edward's time as well, it is unknown).
The invading forces continued to steal land, and shrink the size of the kingdom, encroaching ever closer on the lands near Castle Daventry. The kingdom was expected to fall, until Edward gave his final order and quest to his favorite knight Sir Graham to find the three treasures to save the kingdom.
Potential nations that may have been at war with daventry may include Cumberford and Lycathia, the western and southern kingdoms, as well as kingdoms to the north and east as well. The Swamp is also a small kingdom along the northern to north-eastern border of the kingdom, where monsters may have invaded from. Another possible close nation is Herenna, from there a great dragon once threatened Daventry.