It is training center in Daventry where individuals learn the skills of a defender of the realm, and to join Daventry's army. Graham spent many years training there before he ventured on his first quest.
He spent years scampering up and down ropes as part of his martial training.
The Knight School may be associated with the Royal University.
It is likely located within or near castle Daventry, but training likely also takes place outside in the woods of Daventry as well.