The popularity of Williams's text is undoubtedly aided by its association with CWM RHONDDA, composed in 1905 by John Hughes (b. Dowlais, Glamorganshire, Wales, 1873; d. Llantwit Fardre, Wales, 1932) during a church service for a Baptist Cymanfa Ganu (song festival) in Capel Rhondda, Pontypridd, Wales. Hughes received little formal education; at age twelve he was already working as a doorboy at a local mining company in Llantwit Fardre. He eventually became an official in the traffic department of the Great Western Railway. Much of his energy was devoted to the Salem Baptist Church in Pontypridd, where he served as both deacon and precentor. Hughes composed two anthems, a number of Sunday school marches, and a few hymn tunes, of which CWM RHONDDA is universally known.

At first widely disseminated in leaflet form, CWM RHONDDA gradually was adopted into various hymnals. The tune is named after the valley of the Rhondda River, a coal mining area in Wales. Though composed with simple melodic means, CWM RHONDDA is a vigorous melody in major tonality (contrary to the popular belief that most Welsh tunes are minor). Sing in harmony. The altos and basses may wish to sing the little notes on the last line as they repeat the words "evermore," "strength and shield," and "sing to you." Accompany in a forceful, confident manner.

--Psalter Hymnal Handbook