Authors:

Until the end of the Middle Ages, and in many cases afterwards too, in order to obtain initiation in a trade of any sort whatever--whether that of courtier, soldier, administrator, merchant or workman--a boy did not amass the knowledge necessary to ply that trade before entering it, but threw himself into it; he then acquired the necessary knowledge.

Philippe Ariès (1962). “Centuries of childhood: a social history of family life”, Vintage
Until the end of the Middle Ages, and in many cases afterwards too, in order to obtain initiation in a trade of any sort whatever--whether that of courtier, soldier, administrator, merchant or workman--a boy did not