I became familiar with this song as a child, when I first watched a rerun of the Christmas episode of The Monkees TV comedy series. The Christmas carol is a Spanish villancico (according to the Oxford Dictionary: a form of Spanish and Portuguese song with short stanzas and a refrain, originally a folk song, later used in sacred music) and I enjoy listening to it every Christmas. 🎵🎄🎅🏽😀