Villancico has gained some modern notoriety as a Christmas carol.
Attributed by some sources to Mateo Flech, in others described as anonymous.
The song bears a strong resemblance to Villancico `Falalanlera` (No.27 in the songbook `Cancionero de Upsala`).
The apparently nonsensical syllables `ríu ríu chíu` are often interpreted as representing the nightingale`s song.
The main theme of the song is the Nativity of Christ and the Immaculate Conception.
The refrain that gives Villancico its name is:
Ríu, ríu, chíu, la guarda ribera,
Dios guardó el lobo de nuestra cordera.
`Ríu, ríu, chíu, the kingfisher, God kept the wolf from our Lamb.`
https://en.wikipedia.org/wiki/Ríu_Ríu_Chíu
