Raynouard is sometimes called the founder of Romance linguistics, although his contribution was marked by a fundamental misconception: he believed that the Romance languages were derived from a common post-Latin language, which he called le roman,[7] and not directly from Latin, as is in fact the case.[8] Raynouard's chief works are Choix de poésies originales des troubadours (6 vols., 1816–1821), of which the sixth volume, Grammaire comparée des langues de l'Europe latine, dans leurs rapports avec la langue des troubadours (1821), was separately published; Lexique roman ou dictionnaire de la langue des troubadours comparée avec les autres langues de l'Europe latine (6 vols., 1838–1844).[9] He spent the last years of his life at Passy.