From the mid to late eighteenth century, as the industrial revolution took hold, there was a massive expansion in the economic development of south Wales. Iron-making flourished in emerging towns and settlements, notably at Merthyr Tydfil, Tredegar, and Blaenavon. By the early nineteenth century, south Wales was the most important centre of iron production in the world. Whilst Pontypool was not as competitive as some of the larger ironworks towns, it retained a niche in the metallurgical market, producing specialist tinplate. The japanning industry of Pontypool continued to decline and had ceased by the mid-nineteenth century, by which time the economy of the Pontypool area relied on the iron and coal industries, the tinplate industry and the production of iron rails. The twentieth century witnessed a decline in the heavy industries of south Wales and this had a direct impact on the economy of Pontypool and its district.