The artistic tradition of iron in Catalonia has its roots in Catalan forging, whose splendour peaked in the 17th and 18th Centuries. The quality of Catalan iron, and the work of the forgers, spawned the birth of the iron and steel industry, which in turn gave rise to small industries engaged in the manufacture of keys, fences, door knockers, weapons, etc. Following a period of decadence, which lasted until mid-19th Century, Catalonia made a major effort to revive forging, which reached its zenith during Modernism. The driving forces in this renaissance were Santiago Russinyol, Antoni Gaudí, Puig i Cadafalch and Domènech i Muntaner. By the mid-19th Century, Barcelona had become an industrial city. Ildefons Cerdà had made the Eixample, towards which the city was expanding.