The Eastern Romance languages developed from the Proto-Romanian language, which in turn developed from the Vulgar Latin spoken in a region of the Balkans which has not yet been exactly determined, but is generally agreed to have been a region north of the Jireček Line. That there was language-contact between Latin/Vulgar Latin speakers and speakers of indigenous Paleo-Balkan languages in the area is a certainty, however it is not known which Paleo-Balkan language or languages comprise the substratal influence in the Eastern Romance languages.