Emperor Frederick II. After Pope Innocent IV. had pronounced the Emperor's deposition in 1245 at the Council of Lyon, Frederick in a circular addressed to all princes declared "that it had always been his intention to reduce the ecclesiastics, particularly those of highest rank, to that state and condition in which they had been at the time of the primitive Church, that is, leading an apostolical life and imitating the humility of Christ."
In the following century Marsiglio of Padua in his celebrated work, Defensor Fidei, wrote strongly against the interference of the clergy in temporal matters. He already maintained that the Church consisted of the whole community of Christian men, be they ecclesiastics or laymen. The Pope, according to Marsiglio, can claim no right of supreme judgment in temporal matters, even over the clergy, and the "power of the keys" does not entitle him to place a man under civil disabilities by means of excommunication. Somewhat later, in his Dialogues, William of Ockham expressed similar opinions, though he did not go as far as Marsiglio.
If we endeavour briefly to define the ideas of Hus as far as they differ from the tenets of the Church of Rome—for on most points he was entirely in accord with that Church—we may state that his two leading ideas, closely connected with one another, are his theory of "Christ's law" and his conception of the "true Church." According to Hus the law of Christ, or "God's law"—an expression that afterwards became a watchword of the Hussites—is contained in the writings of the Old and New Testament, which contain all God's commands to man. The second fundamental principle of Hus is his conception of the true Church, which, according to
