Linguistic practicalities seem to have dictated a tacit agreement between John Wesley and the eighteenth-century Welsh evangelicals, by which he confined his activities almost exclusively to English-speaking societies. When he died there were some 600 members, mainly in South Wales, and, although the pace quickened markedly after 1790, Arminian Methodism was weak compared with old Dissent and the new Calvinistic Methodists. Ninety per cent of the population was still Welsh-speaking in the mid-eighteenth century, but Welsh-speaking WM was not established until 1800, when Conference, at the urging of Thomas Coke, appointed Owen Davies and John Hughes as 'missionaries' to Wales.
The work prospered in some parts only, and only in a few towns and villages - notably Coedpoeth, Llanrhaeadr-ym-Mochnant and Tregarth - did WM predominate. But by the beginning of the twentieth century the Welsh work had spread widely enough for there to be two Districts in the North and one in the South. Between 1899 and 1974 the Welsh Assembly, with considerable powers delegated to it by Conference, provided a unifying centre. In 1974 Welsh-speaking Methodism was restructured as one Cymru District. Little knowledge of, or co-operation with, English-speaking Methodism existed until the establishment of a Standing Committee for Methodism in Wales in 1957. This later became the Council for Methodism in Wales and was itself superseded in 1997 by a new, smaller Gymanfa or Welsh Assembly, representing all Districts in Wales.
In 2007 the Conference adopted Standing Orders providing that the work and witness in Wales of Yr Eglwys Fethodistaidd yng Nghymnru/The Methodist Church in Wales should be carried on in two Districts: Synod Cymru, working mainly in the Welsh language, and the Wales Synod, comprising Circuits working mainly in the English language. Y Gymanfa was replaced by Y Cyngor as the leadership and co-ordinating team for this work. Synod Cymru now comprises one circuit.
Unlike Calvinistic Methodism, Welsh WM had no mission field of its own. Its first missionary, to Sierra Leone in 1814, was William Davies ('Davies Affrica'), followed by some 35 others, including H. Penri Davies (1889-1971), E. Armon Jones (1880-1950) and Edward John Jones (1898-1976).
Welsh-speaking WM was, in the nineteenth century, often viewed as 'English' in its features (e.g. the position of the Conference, the training of ministers in England); but in its pattern of worship, its great preaching tradition (Thomas Aubrey, John Evans, D. Tecwyn Evans, E. Tegla Davies, J. Roger Jones), its Sunday Schools, its eventual espousal of radical political issues (Disestablishment, Land Reform), it was by the turn of the century clearly in the mainstream of Nonconformity, even if a junior partner. In 1896 membership stood at just under 20,000 and in 1996 at just under 4,000.