"las mananitas"

Well, nobody really knows. It is just another traditional Mexican song that is nowadays the equivalent to "Happy Birthday". It was meant to be sung at the break of day, thus the "mananitas" ("sweet early mornings") name.

You can hear it here. Those of you don't like the mariachi trumpets, just be glad I didn't link to the Topo Gigio version.

I imagine the reference to David is there just because he had a reputation as a singer, like los pajaritos. There are many psalms that refer to the morning specifically, e.g. Psalm 5: "My voice You shall hear in the morning, O Lord; In the morning I will direct it to you." But I doubt the reference is meant to be that specific.

According to this site, there's a version of it in Campos, Ruben M. El Folklore y la Música Mexicana, Investigación acerca de la cultura musical en México (1525-1925). Publicaciones De La Secretaria De Educación Pública, Talleres Gráficos de la Nación, México, 1928. There may be more information there.

#1 (by which I mean the poster who would be #1 after the OP if the posts were numbered), when you say "nobody really knows" do you mean you have researched the questions OP asked and concluded that nobody really knows, or at least have read a well-sourced article reaching that conclusion, or are you just saying that you don't know and assume that no one else does either? There are lots of things that we think of folklore that can be pretty precisely dated. Mary Had a Little Lamb was written by Sarah Josepha Hale and first published in Boston on May 24, 1830. "Deck the Halls" was first published by Harper & Brothers, New York, in 1881, and as far as anyone can tell is no older than that, although I believe that publication claimed that it was an old Welsh carol.

Isn`t she beautiful? (I love you Lupita, morenita linda)

Las Mañanitas for Our Lady of Guadalupe Patroness of Mexico and the Americas

This is today celebration in the Basilica of Guadalupe, the one with the microphone is the famous Marco Antonio Solis. WOW :oP !!!!

The mexican faith for their virgin is just out of this world... their entire world has to do with her.

Yes, King David was very well known for being an outstanding musician.

"Saul is tormented by an evil spirit. His servants suggest he send for David, "skillful in playing [the harp], a man of valor, a man of war, prudent in speech, and a man of good presence; and the LORD is with him." So David enters Saul's service, and finds favour in his sight, "and whenever the evil spirit was upon Saul, David took the harp and played it with his hand; so Saul was refreshed, and was well, and the evil spirit departed from him."

Another beautiful song that has David as the protagonist is this one:

"Hallelujah" of Leonard Cohen. Was used in Shrek Movie. :o)

Just awesome!

♪...Qué linda está la mañana en que vengo a saludarte... Venimos todos con gusto y placer a felicitarte...♪

That was just to celebrate that we can write in Spanish again... Thank you Virgen Morena!!!

♪...Qué linda está la mañana en que vengo a saludarte... Venimos todos con gusto y placer a felicitarte...♪

That was just to celebrate that we can write in Spanish again... Thank you Virgen Morena!!!
I would like to know how you made the musical note at the beginning and end of the sentence!

Listening at #4's link, which may be the most Mexican thing I've ever seen, it occurred to me that the tune is a waltz. While the waltz has existed since the end of the 18th century (if I recall correctly), I don't think it's likely that there were Mexican folk waltzes prior to, say, the Porfiriato. If I'm right about that, then we've pinned down the origin to within 25 years of 1900.

Anónimo... I make the ♪ sign by typing Alt+13