January 23rd, 1863
"My dear Friend,
"Send me at once the song "Rising of the Lark," Codiad yr Hedydd, in Welsh I think, and get some young lady to play it for you; it is my favorite Welsh air and in most collections."
Elsewhere Frances Rolleston wrote: "I once took a few lessons on the harp just for the poetry of the thing, and bungled a few Welsh airs. 'Codiad yr Hedydd,' 'The Rising of the Lark' was my favourite."
FR had a fondness for songs. She emphasized singing in her infant schools, and credited it with making the children less inclined to fight. She wrote quite a few songs herself, and once claimed that at Filey, men, women and children were singing her songs.
In the January 23rd letter, her purpose in mentioning "Rising of the Lark" was to suggest a tune that her friend's poem might be sung to. Here's a link to the words in English and Welch.