Have a listen. It’s like expensive white chocolate, this music.
And then have another listen.
The music in the top video contains a variation of a theme that is based on the song in the other videos, which is basically a folk tune from the beginning of the 18th century or thereabouts . The Dutch know it as the children’s song “Altijd is Kortjakje ziek” and the English as “Twinkle twinkle little star” and “Baa, Baa, Black Sheep”. There are many other versions, including one in Hungarian, one in French and one in Spanish.
And here is “Twinkle twinkle little star”.
Smetana was a Czech composer who (as did other composers) used it in one of his compositions. His is called “the Moldau”. The Moldau is a river and you can see it bubble and flow throughout the music if you listen carefully.
(Ah, the blessings of having a great music teacher in high school.)
Added later: Ha! I got it wrong! It’s even more complicated! (I guess my high-school teacher gave us a localized version.) There is an older Italian composition called La Mantovana, and that seems to have developed into two folk tunes, which both became very popular.
It’s like someone heard it once and then went home, remembered some of it and added something new, while someone else stayed closer to the original. And then both tunes started to travel.
(I am sure historians will say I got it all wrong! That’s fine by me, LOL.)
At least twelve other classical compositions (by twelve different composers) were inspired by the above folk tune (Twinkle Twinkle Little Star).