Emmerich Kálmán, Die Zirkusprinzessin (1926)

Here's an interestingly weird one.  The idea is that there's this Russian nobleman, Palinski, who was in the past in love with this princess, Palinska.  But his uncle was in love with her too, so he ended up disinherited, and went to join the circus, where he performs as an acrobat under the name "Mister X."  But when he sees the princess at the circus, his hopes are rekindled (apparently they'd never actually met before, as she never recognizes him from the past).  And there's a complicated plot where a spurned suitor of Palinska plots to get "Mister X" to marry her (not knowing who he really is) so that she'll be humiliated at having accidentally married a circus performer.  So this scheme works, and the two are parted.  Forever?  No indeed!  She comes to see him perform an even more death-defying stunt than usual, and they are reunited.  Oh, and also, as always, there's a secondary couple, yada yada.

So at first I was sort of confused: after it's revealed that Palinski is a circus performer, why doesn't he just immediately reveal who he really is and avoid all the further complication?  But then it became clear: it's supposed to be because he didn't want to be with someone who felt humiliated at the idea of marrying someone like that.  And that is an attitude that accords with our sensibilities--but it very much shouldn't accord with theirs!  People aren't supposed to marry outside their social classes!  They're just not!  What this seems to be saying is, sure, if you're a noble you have to marry another noble--but acknowledging this fact is kind of gauche.  An odd thing, for sure.

This is a 1970 German film version--not my ideal way to see it, and I'm sure Seefestspiele Mörbisch would've done a better job--but not too bad, in my view, and the film itself is kind of a historical artifact in its own right.  It's kind of cheap, some music has clearly been cut, and there are some pretty cheesy arrangements; also, Palinski in his Mister X costume looks like he's the hero of an old, zero-budget superhero movie.  But that's okay; I didn't not like it, and you may not not too.