[1] Sources differ as to whether Dr. Parry composed the music for an existing poem by Richard Davies ("Mynyddog Mwynfawr"; 1833–1877) (the common belief) or whether Davies wrote the words to Parry's melody following its use with an English lyric, entitled Arabella, by Thomas Walter Price (Cuhelyn; 1829 - 1869),[2] journalist and poet.
[3] Richard Davies' lyric may have been influenced by the 14th Century love story of Myfanwy Fychan of Castell Dinas Brân, Llangollen, and the poet Hywel ab Einion.
[5] In 1947, Merthyr-Tydfil-born author Jack Jones wrote a book entitled Off to Philadelphia in the morning where he relates the story within some aspects of the life of Parry, weaving facts into his fictional narrative.
Pa le mae'r wên oedd ar dy wefus Fu'n cynnau cariad ffyddlon ffôl?
A boed i rosyn gwridog iechyd I ddawnsio ganmlwydd ar dy rudd; Anghofia'r oll o'th addewidion, A wneist i rywun, eneth ddel, A dyro'th law, Myfanwy dirion, I ddim ond dweud y gair "Ffarwél".
[3] This version[7] is shown above, with the following modernizations of the Welsh language: digter to dicter, cynau to cynnau, ffol to ffôl, melus to melys, ol to ôl, chwareu to chwarau, thânau to thanau, auraidd to euraidd, ammod to amod, ddysglaer to ddisglair, ffarwel to ffarwél.
[12] Cerys Matthews recorded a guitar version for her 2010 album Tir,[13] The song features in John Ford's Academy Award-winning film How Green Was My Valley and also in the last scene of the Swansea-based movie Twin Town, where it is sung by members of many local choirs, including the Pontarddulais Male Choir.
At a key moment of the plot, the protagonist in the 1992 Welsh-language film Hedd Wyn, which was nominated for an Academy Award, sings it to his former fiancée.
It is both played and discussed in the episode "Death and Dust" of the show Midsomer Murders, during a visit to Wales by detectives from an English village.