(Yr) Aval(l)enau/Afallennau (The (Apple(-)Tree(s))/(Apples), or The Apple Tree Stanzas), from Llyfr Du Cærfyrddin (Black Book of Cæmarthen). c AD 620/623 (Twelfth/mid Thirteenth Century AD):

“L. Black Book of Caermarthen XVIL. Text, vol. ii. p. 18. Notes, vol. ii. p. 335” in Skene, William Forbes. The Four Ancient Books of Wales containing the Cymric Poems attributed to the Bards of the Sixth Century, Volume I, pp370-373. Edinburgh: Edmonston and Douglas, 1868.
https://archive.org/download/fourancientbooks01skenuoft/fourancientbooks01skenuoft.pdf

‘L. Black Book of Caermarthen XVII.’ at ISTA - Internet Sacred Text Archive.
https://www.sacred-texts.com/neu/celt/fab/fab065.htm