William Williams, Pantycelyn (also known as Williams Pantycelyn and Pantycelyn) (1717 – January 11, 1791)
is generally acknowledged as Wales's most important hymn writer. He was also one of the key leaders of the 18th century Welsh Methodist revival, along with Daniel Rowland and Howell Harris. As a poet and prose writer he is today considered to be one of Wales's greatest writers.
LIFE
Williams was born in the parish of Llanfair-ar-y-bryn, Carmarthenshire, early in 1717. His family were nonconformists. He was educated locally and intended to become a doctor. This changed when he had a religious conversion while listening to Howell Harris, the evangelical reformer, preaching in Talgarth in 1737.
He took deacon's orders in the Church of England in 1740 and was appointed curate to Theophilus Evans (1693–1767) in the parishes of Llanwrtyd, Llanfihangel Abergwesyn and Llanddewi Abergwesyn. Because of his Methodist activities he was refused ordination as a priest and from then on he committed himself entirely to that movement. He travelled throughout the country preaching and establishing seiadau, local fellowships of Methodist people, for the converts he won. He died in 1791.
In common with many other Welsh people whose names are less than unique, he was known by the nickname or bardic name of Pantycelyn, this being the name of the farm in the parish of Llanfair-ar-y-bryn where he lived for most of his life.
His virtuosity as a hymnwriter also earned him another nickname Y pêr ganiedydd (The sweet singer).

HYMNS
He wrote some of his work in English, but the great majority is in his native Welsh. He published his first work in 1744, the first part of Aleluia, a collection of hymns. This was followed by further collections:
Hosanna i Fab Dafydd (Hosannah to the Son of David), 1751;
Rhai hymnau a chaniadau duwiol (Some godly hymns and songs), 1759;
Caniadau y rhai sydd ar y môr o wydr (The songs of those on the crystal sea), 1762;
Ffarwel weledig, groesaw anweledig bethau (Farwell seen, and welcome unseen things), 1763;
Gloria in exelsis, 1771;
Ychydig hymnau (A few hymns), 1774;
Rhai hymnau newyddion (Some new hymns), 1782.
He also published two collections of English hymns:
Hosannah to the son of David, 1759;
Gloria in exelsis, 1772.
Possibly his best known hymn is Arglwydd, arwain trwy'r anialwch (in English, Lord, Lead Me Through The Wilderness, translated as the English Hymn Guide me, O Thou Great Jehovah), usually sung to John Hughes' Cwm Rhondda .

POETRY
His hymns alone were not his only major contribution to the success of Calvinistic Methodism. He wrote two long poems on theological and religious themes. Golwg ar deyrnas Crist (A view of Christ's kingdom), 1756, deals with the whole history of salvation and God's grace in Christ. Bywyd a marwolaeth Theomemphus, 1764, deals with the religious experience of conversion and Christian living.
He also wrote a series of elegies in memory of various Methodist and other Christian leaders, including Griffith Jones (Llanddowror), Howel Davies (Pembrokeshire), George Whitefield, and Daniel Rowland.