a piece was to visit a master's workshop. Only a certain number of masters could operate within any city's bounds; they were regulated by artisan guilds to whom they had to be affiliated to be allowed to operate and receive commissions. Guilds protected and regulated painting, overseeing production, export trade and raw material supply; and they maintained discrete sets of rules for panel painters, cloth painters and book illuminators. For example, the rules set higher citizenship requirements for miniaturists and prohibited them from using oils. Overall, panel painters enjoyed the highest level of protection, with cloth painters ranking below. Membership of a guild was highly restricted and access was difficult for newcomers. A master was expected to serve an apprenticeship in his region, and show proof of citizenship, which could be obtained through birth in the city or by purchase. Apprenticeship lasted four to five years, ending with the production of a "masterpiece" that proved his ability as a craftsman, and the payment of a substantial entrance fee. The system was protectionist at a local level through the nuances of the fee system. Although it sought to ensure a high quality of membership, it was a self-governing body that tended to favour wealthy applicants. Guild connections sometimes appear in paintings, most famously in van der Weyden's Descent from the Cross, in which Christ's body is given the t-shape of a crossbow to reflect its commission for a chapel for the Leuven guild of archers. Workshops typically consisted of a family home for the master and lodging for apprentices. The masters usually built up inventories of pre-painted panels as well as patterns or outline designs for ready sale. With the former, the master was responsible for the overall design of the painting, and typically painted the focal portions, such as the faces, hands and the embroidered parts of the figure's clothing. The more prosaic elements would be left to assistants; in many works it is possible to discern abrupt shifts in style, with the relatively weak Deesis passage in van Eyck's Crucifixion and Last Judgement diptych being a better-known example. Often a master's workshop was occupied with both the reproduction of copies of proven commercially successful works, and the design of new compositions arising from commissions. In this case, the master would usually produce the underdrawing or overall composition to be painted by assistants. As a result, many surviving works that