The Outlaw of Torn by Edgar Rice Burroughs

Burroughs' second novel concerns the fictitious outlaw Norman of Torn. Set in 13th century England, during the power struggle between King Henry III and Simon de Montfort, Norman is the supposed son of the Frenchman de Vac, once the king's fencing master, who has a grudge against his former employer and raises the boy to be a simple, brutal killing machine with a hatred of all things English.