Works on literature and language written by Jagić started to be published for the first time in the reports of the high school where he worked. In 1863, with his fellow researchers Josip Torbar and Franjo Rački he launched the journal "Književnik". In this journal, he published several articles regarding the problematic of the grammar, syntax, as well that one of history of the language used by Croats. His works were noticed within the Yugoslav Academy of Sciences and Arts (JAZU), founded in Croatia in 1866. His works and polemics were mainly related to verbs, paleography, vocalization of the language, folk poetry, and its sources. At that time he also started publishing a collection of the works written by old Croatian writers.