| Caledfryn | |
| Birth Name: | William Williams |
| Birth Date: | 6 February 1801 |
| Birth Place: | Bryn y Ffynnon, Denbigh, Denbighshire, Wales |
| Death Place: | Groes-wen, Glamorgan |
| Occupation: | Minister, poet, writer, editor |
| Nationality: | Welsh |
| Years Active: | 1820s - 1860s |
William Williams (pen name "Caledfryn" or "Gwilym Caledfryn") (6 February 1801 – 23 March 1869) was a Welsh Congregational minister, poet and literary critic born at Bryn y Ffynnon, Denbigh. He was one of the leading figures in the Welsh Eisteddfod movement and did much to raise the standards of Welsh literature of his time.
He was from a family of weavers at Bryn y Ffynnon. He studied at Rotherham College before becoming ordained as a minister with the Independents in 1829. He was a prominent member of the Anti-Corn Law League, the Peace Society and the Society for the Liberation of Religion which sought to separate the church from the state.[1]
He tried to standardize Welsh as a literary language and wrote a number of articles and criticisms on Welsh poetry, becoming popular in the first half of the 19th century. In 1851 he published Grammadeg Cymreig, an important book of Welsh grammar.[1]
From 1831 to 1868 he served as an editor for numerous Welsh periodicals.[2] He published Cyfarwyddiadur i Ddarllen ac Ysgrifennu Cymraeg ("A Guide to reading and writing Welsh" in 1821; Grawn Awen, a volume of verse in 1826; and Drych Barddonol neu Draethawd ar Farddoniaeth (an essay on Poetry) in 1839.[1]
He spent the last days of his life in South Wales as minister at Groeswen Independent Chapel, near Cardiff in Glamorgan.