population spoke only Welsh. In 1731, Griffith Jones started circulating schools in Carmarthenshire, held in one location for about three months before moving (or "circulating") to another location. The language of instruction in these schools was Welsh. By Griffith Jones' death, in 1761, it is estimated that up to 250,000 people had learnt to read in schools throughout Wales.The 18th century also saw the Welsh Methodist revival, led by Daniel Rowland, Howell Harris and William Williams Pantycelyn. Nonconformity was a significant influence in Wales from the eighteenth to the twentieth centuries. The Welsh Methodist revival of the 18th century was one of the most significant religious and social movements in the history of Wales. The revival began within the Church of England in Wales and at the beginning remained as a group within it, but the Welsh revival differed from the Methodist revival in England in that its theology was Calvinist rather than Arminian. In the early 19th century the Welsh Methodists broke away from the Anglican church and established their own denomination, now the Presbyterian Church of Wales. This also led to the strengthening of other nonconformist denominations, and by the middle of the 19th century, Wales was largely Nonconformist in religion. This had considerable implications for the Welsh language as it was the main language of the nonconformist churches in Wales. The Sunday schools which became an important feature of Welsh life made a large part of the population literate in Welsh, which was important for the survival of the language as it was not taught in the schools. Welsh Methodists gradually built up their own networks, structures, and even meeting houses (or chapels), which led eventually to the secession of 1811 and the formal establishment of the Calvinistic Methodist Presbyterian Church of Wales in 1823. The Welsh Methodist revival also had an influence on the older nonconformist churches, or dissenters the Baptists and the Congregationalists who in turn also experienced growth and renewal. As a result, by the middle of the nineteenth century, Wales was predominantly a nonconformist country. The end of the 18th century saw the beginnings of the Industrial Revolution, and the presence of iron ore, limestone and large coal deposits in south-east Wales meant that this area soon saw the establishment of ironworks and coal mines, notably the Cyfarthfa Ironworks and the Dowlais Ironworks at Merthyr Tydfil. Modern history 19th century The modern history