I've noticed that some of the original 3-part harmony settings, by self-taught singing masters like Billings, have parallel/empty fourths and fifths, but that t

I've noticed that some of the original 3-part harmony settings, by self-taught singing masters like Billings, have parallel/empty fourths and fifths, but that these were removed in later 19th-century 4-part settings by "properly educated" musicians. A good example is "Idumea": https://musescore.com/user/1108766/scores/9410239 https://musescore.com/user/1108766/scores/9410239 (BTW, there are several versions of this song on the Current 93 album _Black Ships Ate the Sky_, of which my favorite is Shirley Collins'.)