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