Indeed it is - understandably! - quite rare to see untranslated Latin and Greek at any length in the core text of historical articles or books. Instead, we translate in the text and the original Latin/Greek usually goes in a footnote for the reader that wants to check the translation.
Iโm working on translating a German text in Catholic theology from the 50s right now. ALL the quotes are in unglossed Latin, indicating the audience at the time was expected to just be able to read it. Theyโre making me find scholarly translations instead.
Catholic theologians? Certainly. But go back a little earlier and we'd be doing that just generally because Latin skills were almost as common as English skills today. It would, however, be normalized Latin with word breaks and no abbreviations - very unlike the original sources from antiquity.
Oh of course, I just thought it was a nice curiosity that the original audience was expected to read Latin, but the new audience is not (itโs a study of Augustine, and it deals with textual variants as wellโa reminder that we donโt have originals)