 Luther’s response was characteristically defiant, later that year burning the bull in front of his supporters in Wittenberg, while himself accusing the Pope of heresy and worse in his reposts which included Against the Cursed Bull of the Antichrist. Having just published his Treatise on Good Works in which he set out his fundamental position on the relation between grace and works, Luther responded to this new situation in three significant writings also published in 1520: Address to the Christian Nobility of the German Nation, The Babylonian Captivity of the Church, and The Freedom of a Christian. The first two texts argue his case against the Pope and key practices of the Church, and the third reflects on how freedom is possible for human beings trapped in sin. Unsurprisingly, given his recalcitrance, Luther’s formal excommunication followed on 3 January 1521, in the bull Decet Romanum Pontificem. This was followed by a summons from Charles V, the recently elected head of the Holy Roman Empire, for Luther to attend the Diet, or regular imperial assembly, at Worms. Choosing to accept the summons despite the great personal risks involved, knowing that in rather similar circumstances the Czech theologian Jan Hus (c. 1372–1415) had been burnt at the stake for heresy, Luther was once more asked to recant, and once more he refused. It is again doubtful whether he actually uttered the famous words “here I stand, I cannot do otherwise”, but he is recorded as summarizing his position by saying: 