 Diez, the principal founder of Romance-language philology, impressed by the comparative methods of Jakob Grimm in "Deutsche Grammatik", which came out in 1819 and was the first to use such methods in philology, decided to apply them to the Romance languages and discovered Raynouard's work, "Grammaire comparée des langues de l'Europe latine dans leurs rapports avec la langue des troubadours", published in 1821.Describing himself as a pupil of Raynouard, he went on to expand the concept to all Romance languages, not just the speech of the troubadours, on a systematic basis, thereby becoming the originator of a new field of scholarly inquiry.Diez, in his signal work on the topic, "Grammar of the Romance Languages," after enumerating six Romance languages that he compared