When did the divergence and differentation of the Romance languages occur? Was this already happening before the fall of the Western Roman Empire?

by remyspam

I was wondering when the differentation of the Romance languages out of (vulgar) Latin occured.

Was this already happening when there still was an overarching governmental apparatus (eg. local dialects, even though at official situations like government, court, etc they used proper Latin), or did this start after the disappearance of the Western Roman Empire?

Niconl

I think this is a better question for /r/asklinguistics. The concept of the subreddit is the same except it's for linguistics! Historians usually don't involve themselves with language.