The Outlaw of Torn by Edgar Rice Burroughs is...

Too Long; Didn't Read

From now on, the old man devoted himself to the training of the boy in the handling of his lance and battle-axe, but each day also, a period was allotted to the sword, until, by the time the youth had turned sixteen, even the old man himself was as but a novice by comparison with the marvelous skill of his pupil. During these days, the boy rode Sir Mortimer abroad in many directions until he knew every bypath within a radius of fifty miles of Torn. Sometimes the old man accompanied him, but more often he rode alone.