Arika Okrent has a great list on Mental Floss about how the languages we speak today are really just some ancient “25 Common Grammar Mistakes That Make You Look Bad” post, a few centuries later.
Sometime around the 7th century, a grammarian got fed up and started collecting all the annoying mistakes that people kept making in Latin. He wrote them up in the Appendix Probi, a straightforward list of the “say this, not that” variety. The most interesting thing about the Appendix Probi is not that it shows that people have always been making usage errors, but that the errors people made in Latin show the specific ways that Latin turned into its descendants, the Romance languages, including Spanish, French, and Italian.
The advice in the Appendix is not so different from what you might see on the same kind of lists for English today. Where our lists warn us to use “dependent not dependant” and “February not Febuary,” the Appendix tells the Late Antiquity Era Latin user that it’s “aquaeductus non aquiductus” and “Februarius non Febrarius.” Despite that advice, the syllable that Latin speakers kept leaving out of Februarius stayed left out in what eventually became Spanish (Febrero), French (Février), and Italian (Febbraio).
Correctness is in the eye of the beholder.