Oman wrote:Before "French" as we know it became a unified language three languages were spoken in what is geographically France today:
- Latin
- Langue d'Oc (gascon, provençal, auvergnat, dauphinois)
- Langue d'Oil of germanic origins spoken north of the river La Loire.
Until the beg. of the 16th century, those 3 lang were spoken is FR.
You forgot to mention Briton, in Brittany, and Alsacian.
And the golden age of Occitan/Provincial was in the Middle Ages, with the love poetry of the trubadors.

