The Darby Furnace, also known as the 'old furnace', was built in 1658 by Sir Basil Brooke. At first sight it appears typical of many 17th century charcoal-fired blast furnaces, however its significance lies in its use by the Quaker ironmaster Abraham Darby for his experiments with coke smelting of iron. In 1709 Darby perfected his technique on this site, which profoundly affected the future development of the English iron industry. The furnace was modified again in 1777, possibly for the manufacture of components of the Iron Bridge, and remained in use until the 1820s. Subsequent development of the Coalbrookdale site encapsulated the furnace within workshop buildings. In the 1950s the furnace was 'rediscovered' and restored. Further restoration and the erection of a protective cover building took place in the early 1980s.