On June 16, 1520, Pope Leo X issued a bull condemning Luther. It listed forty-one propositions from Luther's writings that were declared to be false, dangerous or heretical. If he did not recant, the secular authorities were to seize him and deliver him to the pope. He then would no doubt have been treated as was the Bohemian John Huss, who was burned alive at a stake.
But the secular authorities where Luther was located were sympathetic to him and declined to take action. Their sense of justice was outraged because Luther was condemned without having been given a hearing and an opportunity to defend himself. The bull actually caused public indignation to burst forth against the arbitrary action of the pope.
In Rome and in some other places Luther's books were publicly burned. In reprisal the faculty and student body at Wittenberg gathered outside the Elster gate of the city and burned the papal constitutions, the canon law and works of scholastic theology. Luther added the pope's bull of excommunication to the burning pile.