Gelligaer is unusual in south Wales, in that it mainly retained its agricultural economy until comparatively recently. However, there were small scale industries as far back as 1478, when Llancaiach Foundry is recorded. There were also many small scale pits and drift mines bringing out coal, and there is even the story of the Gelligaer Riot, when blacklegs were brought in to Gelliargwellt level to replace striking miners. This was eventually resolved by swearing on a frying pan!!!! Read the whole story in “Gelligaer a place in history" (pdf, 4.1Mb).
Education became an “industry” that Gelligaer was very well known for – after Edward Lewis left money to open a school for 15 poor boys of the Parish. After various delays, the school finally opened on 1st August 1762 on a site next to the Roman Fort. The creation of this school was well ahead of its time – it wasn’t until 1880 that universal education was established.