I originally posted this question in the Spanish StackExchange but it seems it fits more in here, even though the significance of the word looks more direct in Spanish than English.
My doubt rose up after vaguely remember the words of a professor I had some years ago at the University, but I've been unable to find the source of the history on Internet.
What I remember about what he said is that the story began with a God who is in love with a river and from that relation emerged the mermaids, from which arise the word "encantar" (from the word "cantar"-"to sing" in spanish). This behaviour of seducing people by singing (apart from the extremely beauty of mermaids) is then related with a person who can extract you from this monotony and commonly distraught reality (associated with the life of sailors in a boat) and take you to a new more spiritual and joyful reality without the delusions of the other (associated with the place after death in the case of the sailors).
My question then arises as if anybody can recognize this (intent of) cite and point out the classic text in which it's narrated (or maybe not a classic text but a posterior analysis and analogy of some classic text). I think this history is really beautiful, and wonderful to dedicate to a person who you really love and appreciate :)