He was against the Leipzig Interim (1548) with its compromise on some Catholic usages, and was involved in controversies and quarrels; with Georgius Merula, against whom he maintained the need of exorcism in baptism; with Osiander's adherents in the matter of justification; with his colleague, Nicholas von Amsdorf, to whom he had resigned the Eisenach superintendency; with Flacius Illyricus, and others.
Such external evidence as exists bearing on the origin of the Heliand and the companion poem is contained in a Latin document printed by Flacius Illyricus in 1562.
This is in two parts; the one in prose, entitled (perhaps only by Flacius himself) "Praefatio ad librum antiquum in lingua Saxonica conscriptum"; the other in verse, headed "Versus de poeta et Inter preta hujus codicis."
Under this method might be classed the expositions of Luther, Osiander, Striegel, Flacius, Gerhard and Calovius; and English writers such as Napier, Mede and Newton.
He was attacked by Flacius and Amsdorf, and after a long controversy, full of ambiguities and lacking in the exhibition of guiding principles, he was condemned because his statement savoured of Pelagianism.
The university of Jena, led by Matthias Flacius, was the headquarters of the stricter Lutherans, while Wittenberg and Leipzig were the centres of the Philippists or followers of Melanchthon.
Flacius, on the grounds that the imperial power was not the judge of adiaphora, and that the measure was a trick to bring back popery.
Finally, in 1543, he says that the cause of the difference of final destiny among men lies in the ' It must be admitted, however, that Matthias Flacius saved the Reformation.
It was written in Latin in 1652, its principal author being the reformer Matthias Flacius, who was assisted by other Lutheran theologians.
A preacher named Matthias Flacius held an influential position in ducal Saxony, and taught a form of Lutheranism different from that taught in electoral Saxony.
This breach was widened when Flacius began to make personal attacks on Augustus, to prophesy his speedy downfall, and to incite Duke John Frederick to make an effort to recover his rightful position.
Associated with Flacius was a knight, William of Grumbach, who, not satisfied with words only, made inroads into electoral Saxony and sought the aid of foreign powers in his plan to depose Augustus.
Such in the schools of Europe for about a century and a half after the editio princeps was published by Flacius Illyricus in 1556.