In the following March the Protestants held another conference at Schmalkald, with a view of coming to an agreement as to their conduct in the attempts at unity in the Church. The Elector summoned Melancthon thither, but excused Luther, at his own request. Philip then invited the former, under some pretext or other, to the neighbouring Castle of Rothenburg on the Fulda. Arrived there, he was obliged to be a witness with Butzer, on March 4, 1540, to the marriage of the Landgrave with Margaret. Philip thanked Luther some weeks after for the 'remedy' allowed him, without which he should have become 'quite desperate.' He had kept the name of his second wife a secret from the Wittenbergers; he now told Luther that she was a virtuous maiden, a relative of Luther's own wife, and that he rejoiced to have honourably become his kinsman.
Very soon, however, the news of this unheard of event got wind. The Evangelicals were not less scandalised than their enemies, who in other respects were glad to see the mischief. The first to demand an explanation was the Ducal Court of Saxony, the Duke being so nearly related to Philip's first wife, and on the eve of a quarrel with Philip about a claim of inheritance. The Landgrave's whole position was in jeopardy; for bigamy, by the law of the Empire, was a serious offence. Luther heard now with indignation that the 'necessity' to which Philip had thought himself justified in yielding had been exaggerated. The latter, on the other hand, finding concealment no longer possible, wished to announce his marriage publicly, and defend it. He went so far as to imagine that even if the allies should renounce him he might still procure the favour and consideration of the Emperor. Unpleasant and very painful discussions arose between him, John Frederick, and Duke Henry of Saxony.
Meanwhile, the day was now approaching for the conference at Hagenau. Melancthon was sent there too by the Elector. But on reaching Weimar on June 13, where the prince was then staying, he suddenly fell ill, and it seemed as if his end was close at hand. He was oppressed with trouble and anxiety about the wrongdoing of the Landgrave. The Elector himself wrote reproachfully to Philip, saying that 'Philip Melancthon was disturbed with miserable thoughts about him,' and he now lay between life and death. Luther was sent for by the Elector from Wittenberg. He found the sick man lying in a state of unconsciousness and seemingly quite dead to the world. Shocked at the sight, he exclaimed, 'God help us! how has Satan marred this vessel of Thy grace!' Then the faithful, manly friend fell to praying God for his precious companion, casting, as he said, all his heart's request before Him, and reminding Him of all the promises contained in His own Word. He exhorted and bade Melancthon to be of good courage, for that God willed not the death of a sinner, and he would yet live to serve Him. He assured him he would rather now depart himself. On Melancthon's gradually showing more signs of life, he had some food prepared for him, and on his refusing it said, 'You really must eat, or I will excommunicate you.' By degrees the patient revived in body and soul. Luther was able to inform another friend, 'We found him dead, and by an evident miracle he lives.'
Luther, after this, was taken to Eisenach by his prince, to advise him on the news which he expected to receive there from Hagenau. At Eisenach he and the chancellor Brück had an earnest consultation with envoys from Hesse. Against these, both Luther and Brück insisted that the proceedings which had taken place between Philip and the theologians in respect to his marriage should be kept as secret as a confession, and that Philip must be content to have his second marriage regarded, in the eyes of the world and according to the law, as concubinage. He must make up his mind, therefore, to parry, as best he could, the questions which were being noised abroad about him, with vague statements or equivocations. He would then incur no further personal danger. But any attempt to brazen it out would inevitably land him in confusion and embarrassment, and only increase and continue the damage done to the Evangelical cause by this affair.
The Diet at Hagenau made no further demand on Luther's activity. It was there resolved to take in hand again, at another meeting to be held at Worms late in the autumn, and after further preparation, the religious and ecclesiastical questions at issue. Peaceably-disposed and competent men were to be appointed on both sides for this purpose. Thus Luther was now at liberty to leave Eisenach towards the end of July, and return home, dissatisfied, as he wrote to his wife, with the Diet at Hagenau, where labour and expense had been wasted, but happy in the thought that Melancthon had been restored from death to life.
At Worms the proceedings, in which Melancthon and Eck took a prominent part, were further adjourned to a Diet which the Emperor purposed to hold in person at Ratisbon early in 1541. Here, on April 27, a debate was opened on religion.
Luther entertained very slender expectations from all these conferences, considering the long-ascertained opinions of his opponents. He pointed to the innocent blood which had long stained the hands of the Emperor Charles and King Ferdinand. Still, during the Diet at Worms, the thought arose in his mind that, if only the Emperor were rightly disposed, a German Council might actually result from that assembly. He saw his enemies busy with their secret schemes of mischief, and feared lest many of his comrades in the faith, such as the Landgrave Philip, might treat too lightly the matter, which was no mere comedy among men, but a tragedy in which God and Satan were the actors. He rejoiced again, however, that the falsehood and cunning of his enemies must be brought to nought by their own folly, and that God Himself would consummate the great catastrophe of the drama. And in regard to the fear we have just mentioned, he declared that he, at any rate, would not suffer himself to be dragged into anything against his own conviction. 'Rather,' said he, 'would I take the matter again on my own shoulders, and stand alone, as at the beginning. We know that it is the cause of God, and He will carry it through to the end; whoever will not go with it, must remain behind.'
Between the Diets of Worms and Ratisbon he entered in 1541, with all his old severity, and with a violence even beyond his wont, into a bitter correspondence which had just then begun between Duke Henry of Brunswick—Wolfenbüttel, a zealous Catholic, and morally of ill repute with friend and foe, on the one side, and John Frederick and the Landgrave Philip, the heads of the Schmalkaldic League, on the other. He published against Duke Henry a pamphlet 'Against Hans Worst.' The Duke had taunted him with having allowed himself to call his own sovereign Hans Wurst. Luther assured him, in reply, that he had never given this name to a single man, whether friend or foe; but now applied it to the Duke, because he found it meant a stupid blockhead who wished to be thought clever and all the time spoke and acted like a simpleton. But he was not content with calling him a blockhead; he represented him as a profligate man, who, while libelling the princes and pretending to be the champion of God's ordinances, himself practised open adultery, committed acts of violence and insolent tyranny, and incited men to incendiarism in his opponents' territories. He would let the Duke scream himself hoarse or dead with his calumnies against John Frederick and the Evangelicals, and simply answer him by saying, 'Devil, thou liest! Hans Worst, how thou liest! O, Henry Wolfenbüttel, what a shameless liar thou art! Thou spittest forth much, and namest nothing; thou libellest, and provest nothing.' At the same time this pamphlet of Luther was a literary vindication of the Reformation and Protestantism; here, said he, and not in the popedom, was the true, ancient, and original Christian Church. Luther himself, on reading over his pamphlet after it was printed, thought its tone against Henry was too mild; a headache, he said, must have suppressed his indignation.
Just at this time he had to encounter a fresh and violent attack of illness. He described it, in a letter to Melancthon, who was then at Ratisbon, as a 'cold in the head;' it was accompanied not only with alarming giddiness, from which he was now a frequent sufferer, but also with deafness and intolerable pains, forcing tears from his eyes, something unusual with him, and making him call on God to put an end to his pain or to his life. A copious discharge of matter from his ear, which occurred in Passion Week, gave him relief; but for a long while he continued very weak and suffering. To his prince, who sent his private physician to attend him, he wrote on April 25, thanking him, and adding, 'I should have been well content if the dear Lord Jesus had taken me in His mercy from hence, as I am now of little more use on earth.' He attributed his recovery to the intercessions which Bugenhagen had made for him in the Church.
Whilst he was still feeling his head thus full of pain and unfit for work, he was called upon to give his opinion on the preparations for the religious conference at Ratisbon, and afterwards upon its results.