Although the growth of Merthyr Tydfil as an industrial centre can said to have started with the formation of the Dowlais Iron Company in 1759, leases exist which prove that the people in the 16th century knew of the existence of the mineral wealth of the district. These leases were granted by the Earls of Pembroke and the Windsor family, who were large landowners in the parish. Those who were granted mineral leases laboured chiefly to supply their own domestic needs. For the making of iron, wood was used as the fuel, but the work was done on such a small scale that the appearance of the district was not altered very much.

Within the area of the parish there were nearly 100 small farms. These low, thatched, white washed dwellings stood in the open spaces. Of the larger houses the chief were the Court House, the Parsonage, the Mill, the Mardy, or Morlanga, and Tredyrhiw House. As in earlier times, the fire was placed in the middle of the room, while all around were to be seen the furniture and knick-knacks, some of which are preserved in museums today.

There were a number of woollen factories in the parish. Wool Street, which was situated near the Parish Church, reminds us of the factory which stood at Caedraw. Another stood on the banks of the Morlais at Gellifaelog, Dowlais.

Little had been paid to the education of Welsh people in the previous centuries, but at this time there came a national desire for more opportunities to increase knowledge. A response to this call soon came, for Griffith Jones, of Llanddowror, a kind hearted clergyman, decided to establish schools were old and young would be taught to read. The Bible was used as the class reading book and Griffith Jones was able to make arrangements for copies to be purchased much more cheaply than had formerly been the case.

As a result of the increased reading of the Bible, and the work of the religious reformers, the people of the district became more cultured and refined.

A letter from the Rector of Merthyr to Griffith Jones:-

January 27, 1754 Merthir Tydvil in Glamorganshire

Reverand Sir. - In justice to the Bearer Hereof, D-T-, who is employed to teach the Children of the Poor Inhabitants of this Parish, I think myself hereby bound to Certify any whom it may concern, that he has used the same Industry and Diligence in instructing the children in his care for the last Quarter before; which plainly appears from the farther Improvement they have acquired under his tuition since I sent my first Account of his good Behaviour, and that both in teaching them to read well the Welch Language and readily to say by heart the Church Catechism, which contains the Fundamentals of our holy Religion. The Children's Parents therefore heartily join with me in our repeated Thanks to you and the Pious Benefactors of this exceedingly well bestowed Charity humbly requesting the Favour of having the Bearer's further continuance amongst us for another Quarter at least. Which will give infinite Pleasure both to me and my Parishoners.- I am, etc,

Tho.Price, Rector of Merthir aforesaid.