The division of labour that underlies the practice of industrial design did have precedents in the pre-industrial era. The growth of trade in the medieval period led to the emergence of large workshops in cities such as Florence, Venice, Nuremberg, and Bruges, where groups of more specialized craftsmen made objects with common forms through the repetitive duplication of models which defined by their shared training and technique. Competitive pressures in the early 16th century led to the emergence in Italy and Germany of pattern books: collections of engravings illustrating decorative forms and motifs which could be applied to a wide range of products, and whose creation took place in advance of their application. The use of drawing to specify how something was to be constructed later was first developed by architects and shipwrights during the Italian Renaissance.