Most of medieval industry was organised under the guild system with crafts forming their own corporations by the 13th or 14th century. Guilds consisted of a hierarchical progression from apprentices (new employees/trainees), to journeymen (salaried employees), to masters (heads of artisan workshops). Apprenticeship was a hands-on practical education of an apprentice by a master in the specific skills of a particular artisanal occupation. Women were trained in formal apprenticeship in far fewer numbers than men, and rarely became masters. Generally, the structure of apprenticeship contracts was similar for male and female apprentices. Children were apprenticed at various ages. The length of apprenticeship varied across occupations. In the best of circumstances apprentices enjoyed a kind of surrogate family in the master’s household while acquiring a skill. The guild system with its reliance on apprenticeship training has come under considerable criticism in modern scholarship for lack of efficiency, the stifling of innovation, and the restriction of economic development, particularly that of market capitalism. In defence, scholars point to the transmission of skills via apprenticeship, along with the preservation of quality standards, financial support, and mediation and negotiation among members and with municipal and royal administrations.