The Theses had been written in Latin for the educated class but they were now speedily translated into German and spread like wildfire among all classes throughout the country. Luther's underlying principle of "salvation through simple faith" was in sharp contrast with the theory of "good works," on which the indulgences rested. "The Christian who has true repentance," wrote Luther, "has already received pardon from God altogether apart from an indulgence, and does not need one; Christ demands this true repentance from every one." Luther's attitude provoked spirited discussion throughout the Germanics, and the more discussion, the more interest and excitement. The pope, who had dismissed the subject at first as a mere squabble among the monks, was moved at length to summon Luther to Rome to answer for the Theses, but the elector of Saxony intervened and prevailed upon the pope not to press the matter. [Sidenote: Disputation at Leipzig, 1519] The next important step in the development of Luther's religious ideas was a debate on the general question of papal supremacy, held at Leipzig in 1519, between himself and an eminent Catholic apologist, Johann Eck. Eck skillfully forced Luther to admit that certain views of his, especially those concerning man's direct relation with God, without the mediation of the Church, were the same as those which John Hus had held a century earlier and which had been condemned both by the pope and by the great general council of Constance. Luther thereby virtually admitted that a general council as well as a pope might err. For him, the divine authority of the Roman Catholic Church ceased to be. [Sidenote: Separation of Luther from the Catholic Church] Separation from the traditional Church was the only course now open to Luther and this was consummated in the year 1520. In a series of three bold pamphlets, he vigorously and definitely attacked the position of the Church. In the first--_An Address to the Nobility of the German Nation_--Luther stated that there was nothing inherently sacred about the Christian priesthood and that the clergy should be deprived immediately of their special privileges; he urged the German princes to free their country from foreign control and shrewdly called their attention to the wealth and power of the Church which they might justly appropriate to themselves. In the second--_On the Babylonian Captivity of the Church of God_--he assailed the papacy and the whole sacramental system. The third--_On the Freedom of a Christian Man_--contained the essence of Luther's new theology that salvation was not a painful _progress_ toward a goal by means of sacraments and right conduct but a _condition_ "in which man found himself so soon as he despaired absolutely of his own efforts and threw himself on God's assurances"; the author claimed that man's utter personal dependence on God's grace rendered the system of the Church superfluous.