Friedrich Wilhelm II (r. 1786-1797) and Friedrich Wilhelm III (r. 1797-1840) of Prussia, in an attempt to support the weak trade position of their country, promoted the use of iron, which started to be extensively mined in Friedrich II's reign. Karl Friedrich Schinkel (1781-1841), in his capacity as chief architect of the Department of Building Works of Prussia, from 1806 employed iron not only for building purposes but also for decorative works such as monuments, jewellery and furniture. In 1821 Schinkel was appointed to the board of the newly founded Königliches Preussisches Gewerbeinstitut (Royal Prussian Institute for Trade and Crafts) and his influence on the future of Prussian design greatly increased. He made cast-iron the principal manufacturing material, as it suited both serial production and expressed the Neoclassical idiom particularly well. The institute supplied its designs to the Königliche Eisengiesserei Berlin, which flourished 1804-1866 and also cast the furniture for Schinkel's commissions. His designs reflected the influence of both classical ideas from Greek, Roman and Egyptian prototypes, as well as those of the contemporary French Empire and English Regency. He simplified these designs with the aim to 'imbue each structural part with beauty and truth to its own function'.