One of the greatest promoters of Protestantism in Europe was Flacius Illyricus (Matija Vlacic, born in Labin in Istria, 1520-1575). As a young Croatian philosopher, at the age of 24 he was appointed to be a professor of Hebrew and Greek at the University of Wittenberg, the center of Protestantism. The bibliography of his work is enormous – three hundred books and brochures. His “Catalogus testium veritatis” (Magdeburg, 1555) represents a tremendous historical documentation, probably the best polemical book of his time. French edition appeared in Strasbourg in 1526 and in Lyon in 1597. His pamphlet “Contre la principauté de l’évêque de Rome” was printed in Lyon in 1563. He wrote also about Croatian churches that ever since had liturgy in the Croatian version of the Old Church Slavonic language, using holly books written in the Croatian Glagolitic Alphabet. He was the organizer, editor in chief and the chief writer of the famous “Ecclesiastica historia” (The History of the Church), that appeared in 13 volumes in Basel.

Flacius Illyricus: Clavis Scriptuare Sacrae, Regensburg, 1567
(from the 2006 exhbition in NSK, Zagreb)

His greatest linguistic work is “Clavis Scripturae Sacrae” (The key to the Sacred Script, it contains about 7.5 million characters), Regensburg, 1567, analyzing lexicographically the content of the Old and New Testament. He is considered to be the founder of hermeneutic philosophy. When writing about Istria (peninsula in the Adriatic), he calls it `the sweetest homeland’.

There is a work of a famous French polyhistor Guillaume Postel, with the preface written by Flacius Ilyricus (Matija Vlacic):

Postel Guillaume: Epistola Guilemi Postelli ad C. Schwenkfeldium, cum prefacione m. Mathiae Flacci Illyrici, Jenae, 1556. (see [Marianna D. Birnbaum, p. 510])

It is interesting that Guillaume Postel presented Croatian Glagolitic Scritp in one of his books, calling it Alphabetum Hieronymianum seu Dalmaticum, aut Illiricum.