Old French
Old French was the Romance dialect continuum spoken in the northern half of modern France and parts of modern Belgium and Switzerland from around 1000 to 1300. It was then known as the langue d'oil. This was different from the langue d'oc (Occitan language, also then called Provencal), whose territory bordered that of Old French to the south.
The Old Frankish language added many words to Old French after the conquest by the tribe of the Franks, of the portions of Roman Gaul that are now France and Belgium, during the Migration Period.
References
French language