FLACIO (VLACIC), MATTIA. — Protestant scholar, known as F. Illyricus, born in Albona (Istria) on March 3, 1520, died in Frankfurt on March 11, 1575. Having entered the Franciscan Order, he was sent by his uncle Baldo Lupetino, who was provincial of Venice, in 1539 to complete his studies in Germany, where he embraced Lutheran errors and soon distinguished himself as one of the most ardent supporters of the German reformer.
Professor of Hebrew in 1544, he led an errant life, driven from city to city for his radical stance and his outright opposition to the Austrian Interim and the Adiaphorists, led by Philipp Melanchthon (v. ADIAPHORA). F. was the recognized leader of the Gnesio-Lutherans, and as such incurred Melanchthon’s unrelenting wrath. Likewise, he clashed with Georg Major and the synergist faction he led, as well as with Andreas Osiander (v.), champion of Luther’s figure, especially in his book on the marks of the true religion: *De falsa papistarum religione* (Magdeburg, 1549). F. carried their doctrines to their extreme conclusions, asserting, among other things, that final salvation depends solely on God’s gratuitous judgment. Justification is to be attributed immediately to the merits of Christ. After teaching for several years at the University of Wittenberg, he vigorously attacked Catholic doctrine, particularly in two works: *Catalogus testium veritatis qui ante nostram aetatem reclamarunt Papae* (Basel, 1550) and *Clavis Scripturae Sacrae* (ib., 1567).
For a time during his stay in Jena, he played a leading role in the *Magdeburg Centuries* (v. CENTURIATORS OF MAGDEBURG). Shortly before his death, he was struck by yet another decree of expulsion while in Frankfurt.