Sebastian Castellio

Sebastian Castellio was likely the first Christian prophet of religious liberty. As a young man in 1540, he witnessed the public execution of three Lutherans, whom the Inquisition considered heretics. This so profoundly affected Castellio that he forsook the Catholic Church and made his way to Geneva, where John Calvin appointed him as schoolmaster.


He was the only divine who ministered to victims of the plague, but his request for ordination was denied because of his views. For one thing, he would not accept Calvin’s view that some people—the reprobates—are predestined to damnation.

He moved to Basel, where after years of poverty, he found a position as a professor of Greek. While there, he learned that Michael Servetus, an amateur theologian, had been burned at the stake for denying the doctrine of the Trinity. Calvin held that it was the responsibility of the magistrate to defend true doctrine, thereby maintaining the honor of God. As a defense of his actions, in February 1554 Calvin published a treatise titled Defense of the orthodox faith in the sacred Trinity in which he presented arguments in favor of the execution of Servetus for diverging from orthodox Christian doctrine.

Castellio responded immediately. He wrote a book, published anonymously, titled On Heretics: Whether They Should Be Punished by the Magistrate, and other works on this theme. Jesus’ message is mercy and forgiveness. There could be no greater sin than killing a human in the name of God. Asked the definition of a heretic, he said, “After diligent investigation . . . I can discover no more than this, that we regard those as heretics with whom we disagree.”

“We do not dispute concerning the way to Christ, but on his relationship to God the Father, on the Trinity, predestination, freedom of the will, the nature of God, the angels, the state of the soul after death—on a multitude of things which are not essential to salvation; things which, in truth, we can never know unless our hearts are pure, for these things must be comprehended spiritually.”

As Castellio noted, all sects are certain that their views are based on the Word of God. “Calvin says his are certain, and they theirs. He says they are wrong and wishes to be the judge and so do they. Who shall be the judge? Who made Calvin the judge of all the sects, that he alone should kill?”

In answer to Calvin’s question about how the true church was to be recognized, Castellio answered, “By an assured faith concerning things that are hoped for, not known, by love which is better than faith and may be clearly discerned, by the doctrine of piety which is to love your enemies, bless those who curse you, to hunger and thirst after righteousness and to endure persecution for righteousness’ sake.”

He was the designated successor to Desiderius Erasmus in continuing his work of the reconciliation of Christianity in the Protestant, Anabaptist, and Catholic branches, and prophetically predicted the French Wars of Religion, and potentially the destruction of Christianity in Europe, if Christians could not learn to tolerate and reach each other by love and reason rather than by force of arms, and in short become real followers of Christ, rather than of bitter, partisan, and sectarian ideologies. 

This is an excerpt from All Saints: Daily Reflections on Saints, Prophets, and Witnesses for Our Time, and the Wikipedia article on Castellio. All Saints is available from Crossroads Publishing, Amazon and other retailers. If your local bookstore is unable to order it, here is a link to the publisher’s page for the book: Crossroads Publishing Link for All Saints and here is the Amazon page for the book: Amazon link for All Saints