On the eve of the Civil War in 1642 there was much sympathy for the royalist cause in Wales. But the parliamentarians also found adherents among some landowners, such as Robert Devereux, 3rd earl of Essex, and Thomas Myddelton, as well as among individuals committed to the Puritan cause, such as the writer Morgan Llwyd and the zealous soldier John Jones of Maesygarnedd. It was mainly in the border counties and in Pembrokeshire, however, that Puritan influence and commercial contacts served to win support for the parliamentary cause. The imposition of parliamentary power on Wales and the sequestration of royalists’ property incurred resentment, and Puritan missionaries found themselves labouring in what they believed to be a dark corner of the land. The Act for the Propagation of the Gospel in Wales (1650) set up a coercive authority encompassing both political and religious life, but state intervention remained largely unproductive.

Nonetheless, the Interregnum saw the formation of Dissenting congregations, which were to lay the foundations for some of the abiding influences of modern Welsh life. The most radical were the Quakers who, making particular headway in Montgomeryshire and Merioneth, penetrated not only Anglicized border territory but also the heart of the Welsh-speaking areas. Incurring the animosity of churchmen and other Dissenters alike, they were repressed with a severity experienced only by Roman Catholics and forced into emigration to Pennsylvania, in large numbers. On the other hand, small gathered churches of Congregationalists and Baptists, whose theology was Calvinist and whose belief and personal conduct were governed by a strict code expounded in their church covenant, established the Dissenting tradition within rural communities and small towns.

In the 18th century Methodism became a new and potent influence. Launched by a revival movement of great intensity in the years after 1735, Methodism was sustained within the established church by means of local societies and a central association. The combined influences of the old Dissent and the new Methodism, however, eventually transformed the religious adherence of the Welsh people at the expense of the established church. Although served by innumerable men of learning and devotion, among them Griffith Jones, whose circulating schools contributed immeasurably to the growth in literacy, the church was racked by poverty and inadequate leadership. Thus the Methodist secession from the Anglican church made the ultimate triumph of Nonconformity inevitable.

Methodism and Dissent were not the only influences at work in 18th-century Wales. The resilience of a native culture no longer able to depend upon traditional sources of patronage showed itself in a patriotic fervour to preserve a cultural heritage threatened by progressive Anglicization. Although its proponents drew upon Welsh scholarly achievements, notably those of Edward Lhuyd, Wales had no academic institutions capable of appraising critically the work of romantic antiquarians who looked back to Celtic myth and British druidism. Yet despite its shortcomings, the 18th-century cultural movement was an important expression of a preindustrial society’s resourcefulness in protecting its heritage. One of its key figures was Edward Williams (Iolo Morganwg), whose endeavours encompassed a vast range of literary and historical studies and who also represented the political radicalism inspired by the French Revolution. Radical convictions were held only by a small minority, some of them eccentrics and others distinguished expatriates, but their endeavours marked a significant stage in the emergence of a distinctively Welsh political consciousness.

The growth of industrial society

By 1800 Wales was rapidly ceasing to be a land whose people were almost entirely dependent upon a rural economy. Industrial development, already present in certain localities, now took place on a larger scale. There was considerable development in the coalfield of northeastern Wales; in the southwest, in Swansea, copper smelting, in particular, served to make the town an important metallurgical centre, and for a period it also could count fine porcelain among its range of manufactures. The main industrial expansion occurred, however, with the growth of substantial ironworks on the northern rim of the South Wales coalfield in Glamorgan and Monmouthshire. Not hitherto served by any major urban centres, the area now became densely populated, largely as a result of immigration from other areas of Wales. A natural increase in population accelerated considerably by the late 18th century, with an estimated population for Wales of 450,000 in 1750 rising to 587,245 by 1801. The population continued to grow, again mainly by natural increase, to 1,163,139 by 1851 and to 2,012,875 by 1901. It was only in the following decade that immigration into Wales occurred on a massive scale. In this period 126,529 persons, the majority of whom came from outside Wales, migrated into Glamorgan and Monmouthshire alone, further enlarging the population of the counties that had benefited most from the internal migration of the earlier decades.

Industrial growth made it possible for large numbers of people whom the rural economy could not sustain to find a livelihood within Wales, and the industrial communities of Glamorgan and Monmouthshire contained a substantial Welsh-speaking element throughout the 19th century. Merthyr Tydfil grew rapidly to become the main urban centre of a new industrial society, but it sadly lacked the facilities normally associated with settlements of a more gradual growth. Conditions in the mining areas were harsh; workers were subjected to long hours and low wages, their children were often forced to work at the mines from a young age, and their families lived in wretched and overcrowded circumstances. It was in Merthyr Tydfil that industrial and social unrest, first expressed in wage-related disputes and sporadic rioting in several areas, erupted into a serious rising in 1831. In the following years the workers’ main channel for expressing their aspirations was Chartism, which found its most forceful manifestation in the insurrection at Newport in 1839. Rural Wales, too, was subject to social unrest, and between 1839 and 1843 the Rebecca Riots, ostensibly directed against the exaction of road tolls, gave expression to the underlying difficulties of the tenant farmers of southwestern Wales.

Improved economic conditions from the middle years of the century onward ushered in a period of comparative quietude in industrial Wales. A new phase in industrial growth, brought about by the exploitation of the steam-coal reserves of Glamorgan and Monmouthshire during the last decades of the century, created new valley communities that drew immigrants both from rural and industrial settlements in Wales and from elsewhere. The growth in coal exports led to the building of docks on the coast between Newport and Swansea, notably at Cardiff, while increasing dependence on imported ore led to the relocation of the growing steel industry to areas in close proximity to the coast.

Political radicalism

Wales only gradually embraced the radicalism that came to be regarded as its traditional political allegiance. The political exigencies of the years of the French wars of the Napoleonic period forced the Methodists, in particular, into a passivity that was underlined by a sterner interpretation of Calvinist theology. Political passions were aroused, however, by the moral indictment of the Welsh nation, and especially its Nonconformity, carried in the Report of the Commissioners for Education in 1847. The Welsh, especially the women, were portrayed as depraved and immoral, backward and ignorant. Even the more able ones among them were thought to be impeded by their theological wrangling and often by their lack of English. The growth of a Welsh-language periodical press from its largely denominational origins into a distinctively radical force proved an important influence in rural and industrial Wales alike. By the later years of the 19th century, following the franchise reforms of 1867 and 1884, the hegemony of Welsh Liberal Nonconformity was well established. The passing of legislation specifically concerned with Wales, such as the Welsh Intermediate Education Act (1889) and the Church Disestablishment Act (1914), was a parliamentary success matched in cultural life by the founding of three university colleges and the federal University of Wales and the securing of a royal charter for the establishment of the National Library of Wales and the National Museum of Wales. The attempt by Welsh Liberal associations to secure a representative assembly reached its peak with the Home Rule movement of 1886–96, but it was wrecked by dissension within the associations.