Welsh Methodist preacher and author, born on 7 January 1722 at Llansadurnen, near Laugharne, Carmarthenshire and educated at Carmarthen grammar school. He was converted under George Whitefield's preaching in April 1743 and after teaching for a while was ordained deacon in 1745. He served as a curate, but was dismissed from several parishes because of his Methodist leanings. Joining the Calvinistic Methodists in 1747 he preached widely before marrying and settling at Llandyfaelog, north of Kidwelly, the following year. There he gave himself to extensive editing, translating and writing, notably an annotated Welsh Bible (1767-1770) which proved very popular. He edited a volume of Welsh hymns in 1759 and published Hymns on Various Subjects in 1771.
Despite his outstanding contribution to Welsh Methodism, he was expelled by the Methodists in 1791 on suspicion of heretical views on the Persons of the Trinity. He is remembered particularly as the translator of the opening verse of William Williams's 'Guide me, O thou great Jehovah' (HP 437; SF 465). He died at Llandyfaelog on 8 August 1796. His son Peter Bailey Williams (1763-1836) and grandson Henry Bayley Williams (1805-1879) both became Anglican priests.