The Cyfarthfa works commenced in 1765 by Anthony Bacon. Work on the first coke blast furnace began in August 1766. It was probably brought into blast in Autumn 1767. The heyday of the works was under the Crawshay family from 1794-1810. Producing cannon critical to the Navy resulting in a visit from Admiral Nelson in 1802. By 1819 it had six blast furnaces, producing 23,000 tons of iron. The works continued to provide high-quality iron to the Industrial Revolution, but lost its position as the leading ironworks in Merthyr Tydfil to its rival, Dowlais Ironworks. Competition and rising iron ore costs (imported by this point) took their toll and given a reluctance to switch to steel, the works closed in 1875. The family reopened the works, but soon closed it again for a costly, long rebuild to a steel works completed in 1884 known as Crawshay Brothers, Cyfarthfa, Limited. The works were sold to Guest, Keen & Nettlefolds Ltd, proprietors of Dowlais Ironworks in 1902. By 1910, the steelworks again closed. It briefly reopened in 1915 for the production of materials for World War I, but closed for the last time in 1919 being dismantled in 1928. The closure was a devastating blow to the local economy. Today at NGR SO038068 can be found the huge & impressive furnace bank containing 6 original furnaces, to the front of these are the bases of the later steel furnaces.