Hello historians of Reddit. I've noticed this recurring melody in music from movies set in the Enlightenment era, usually during royal/aristocratic ball scenes. The best example I can find is from What Child Is This (0:34-0:40 in this one, just imagine it with more tremolo). I know that it's a 19th century piece, but that melody is very close to what I'm describing.

Is there some music theory/history associated with that? This isn't just a Hollywood thing, I also hear that melody when I listen to actual pieces from that period, like Bach or Lully. I assume the musical period/style I'm referring to would be Baroque, since I don't notice that melody in classical music, like Mozart's or Beethoven's.