 In contrast with this “irenic” humanist approach, Luther defended the protestant idea of the individual conscience bound only to the word of God, which marks the limits of the authority of the church as well as of the secular powers of the state (Luther 1523). The traditional arguments of free conscience and of the two kingdoms were radicalized in this period. The protestant humanist Sebastian Castellio (1554) attacks the intolerance of both Catholic and Calvinist practices and argues for the freedom of conscience and reason as prerequisites of true faith. In this period, decisive elements of early modern toleration discourse were formed: the distinction between church authority and individual religious conscience on the one hand and the separation of religious and secular authority on the other.