Attributed by some sources to Mateo Flecha, described as anonymous by others.
Villancico has gained some modern fame as a Christmas carol.
The song bears a strong resemblance to the Villancico `Falalanlera` (No.33 in the same songbook).
Obviously nonsense syllables `ríu ríu chíu` are often interpreted as representing the song of a nightingale.
https://classic-online.ru/ru/production/186298
https://en.wikipedia.org/wiki/Ríu_Ríu_Chíu
https://en.wikipedia.org/wiki/Cancionero_de_Upsala
