The reception accorded to the papal document varied according to the views of the local authorities and the state of public feeling in the different cities and provinces. Thus, while its publication was welcomed in Cologne, Mainz, Halberstadt, and Freising, it was received with very mixed feelings at Leipzig and at Erfurt. Frederick of Saxony, to whom Leo X. had addressed a personal appeal, refused to abandon Luther's cause unless it were proved from the Scriptures that he was wrong. He did, indeed, suggest that Luther should write a respectful letter to the Pope, but his suggestion passed unheeded. At first Luther pretended that the Bull was a forgery brought forward by Eck to discredit him, but when this line of defence proved useless, he boldly attacked the papal pronouncement in his pamphlet, /Against the Bull of Anti-Christ/, in which he denounced Leo X. as a heretic and apostate, an enemy of the Holy Scriptures, a tyrant, and a calumniator. Lest, however, the courage of his supporters might be overcome by the terrors of excommunication, he issued an appeal from the sentence of the Pope to the judgment of a future General Council. Finally, on the 10th December, 1520, in the presence of an immense concourse of the citizens and students of Wittenberg, he burned publicly the papal Bull and the writings of his political opponents. On this occasion he proclaimed his intention of overthrowing the ecclesiastical organisation, and of introducing a new theological system. For the future it was to be war to the knife against the Pope and the Church, and he called upon German patriots and all true friends of personal liberty to take their stand by his side in the conflict that had been begun.