A shift in language was expedited with the loss of men during the First World War and the resulting economic turmoil.
English gradually began to replace Welsh as the community language, as shown by the decline of the Welsh language press in the town.
The Gadlys Ironworks was established in 1827 by Matthew Wayne, who had previously managed the Cyfarthfa ironworks at Merthyr.
The Gadlys works, now considered an important archaeological site, originally comprised four blast furnaces, inner forges, rowing mills and puddling furnaces.
A large proportion of the early migrant population were Welsh speaking, and in 1851 only ten per cent of the population had been born outside of Wales.