"}Something underrated is that under the “one-drop rule” most of the original founders of the NAACP wouldn’t have passed the “paper bag test” and might charitably be called “mixed-race” today
There was this “tragic mulatta” trope in late 19th cen. American literature, one strain was “quadroons” or “octoroons” occupying a “white” station in life before they were exposed by family records, there’s similar stuff with Indian “untouchable” castes and Japanese “burakumin”
Isn’t there also a thing in Europe about secret gypsy/Romani or Jewish heritage? And I was under the impression that Spanish people (people from Spain!) were looked upon with a bit of suspicion in the US in the past as being likely to secretly have Jewish and/or “Moorish” ancestors, which meant Muslims, from North African to Arabic ethnicity.