Ignatius (Vatroslav) Vikentievich Yagich (July 6, 1838, Varazdin, Croatia – August 5, 1923, Vienna, Austria) – Croatian Slavic philologist, folklorist, linguist, literary critic, historian, paleographer and archeographer. Academician of the St. Petersburg Academy of Sciences (1880). One of the largest experts in the field of Slavic linguistics in the second half of the 19th century. Doctor of Philology (1870), professor (1863). Member of the Yugoslav Academy of Science and Arts, Russian, Berlin, Vienna, Krakow, Serbian Academy of Sciences, the Royal Society of Czech Linguists. Yagich founded the first international Slavonic journal, Archiv für slavische Philologie (1875-1929), one of the best at the end of the 19th century, of which he edited for forty years. The journal played the role of a unifying center in the field of Slavic studies. In Vienna, I. V. Yagich founded a Slavic seminary at the university, making it the central school of Slavic studies for young scientists from different countries. In all his scientific research, V. Yagich constantly pointed out the need for linguistics to converge with the history and theory of Slavic literatures – Old Slavonic, Old Russian, Serbo-Croatian, Old Bulgarian, as well as with the study of their relationships and connections with Byzantine literature.