It is suggested that various developments in technology and mathematics allowed the development of the professional ‘gentleman’ architect, separate from the hands-on craftsman. Paper was not used in Europe for drawing until the 15th century but became increasingly available after 1500. Pencils were used more often for drawing by 1600. The availability of both allowed pre-construction drawings to be made by professionals. Concurrently, the introduction of linear perspective and innovations such as the use of different projections to describe a three-dimensional building in two dimensions, together with an increased understanding of dimensional accuracy, helped building designers communicate their ideas. However, the development was gradual. Until the 18th-century, buildings continued to be designed and set out by craftsmen with the exception of high-status projects.