The South Germans readily accepted the invitation. The Strasburgers passed it on to the Swiss, and specially desired that Bullinger from Zurich might take part in the conference. The Swiss, however, who had received no direct invitation from Wittenberg, declined the proposal; they wished to adhere simply to their own articles of faith, which they had just formulated anew in the so-called 'First Helvetian Confession,' and which had expressly acknowledged at least a spiritual nutriment to be offered in the Sacramental symbols. They could not see anything to be gained by personal discussion. But they requested that their Confession might be kindly shown to Luther, and Bullinger sent him special greetings from himself and the Evangelical Churches of Switzerland. The preachers who were sent as deputies to Eisenach from the various South German towns, journeyed by way of Frankfort-on-the-Main, where just then the Schmalkaldic allies were assembled. On May 10 they went on, eleven in number, to Eisenach; they represented the communities of Strasburg, Augsburg, Memmingen, Ulm, Esslingen, Reutlingen, Furfeld, and Frankfort.

At the last moment the whole success, nay even the very plan of the conference, was imperilled. Melancthon had already been anxious and despondent, fearing a fresh and violent outburst of the controversy as a consequence of the impending discussion. Luther had just been freshly excited against the Zwinglians by a writing found among the papers Zwingli left behind him, and which Bullinger had published with high eulogiums upon the author, and also by a correspondence that had just appeared between Zwingli and Oecolampadius. Butzer, however, and his friends still wished to maintain their intimacy with these Zwinglians, and this correspondence was prefaced by an introduction 'from his own pen. Furthermore, letters had reached Luther, representing that the people in the South German towns were not really taught the true Bodily Presence in the Sacrament. In addition to this, severe after-effects of his old illness again attacked him, rendering him unfit to travel to Eisenach. Accordingly, on May 12 he wrote to the deputies begging them to journey as far as Grimma, where he would either appear in person, or, if too weak, could at all events more easily communicate by writing to them and his friends.

The deputies, however, came straight to him at Wittenberg. In Thuringia they were joined by the pastors Menius of Eisenach and Myconius of Gotha, two of Luther's friends who with him were honestly desirous of unity. The constant personal intercourse kept up during the journey served greatly to promote a mutual understanding.

Thus on Sunday, May 21, they arrived at length at Wittenberg.

The next day, the two Strasburgers, Capito and Butzer, held a preliminary interview with Luther, whose physical weakness made any lengthy negotiations very difficult. He expressed to them candidly and emphatically his desire, repeated again and again, that they should declare themselves at one with him. He would rather, however, leave matters as they had been, than enter into a union which might be only feigned or artificial, and must make bad worse. With regard to the Zwinglian publications, Butzer answered that he and his friends were in no way responsible for them, and that the preface, which consisted of a letter from himself, had been printed without his knowledge and consent. With regard to the doctrine of the Sacrament, the only question now left to decide was whether the unworthy and godless communicants verily partook of the Lord's Body. Luther maintained that they did: it was to him the necessary consequence of a Bodily Presence, such as took place simply by virtue of the institution and sure promise of Christ, by which faith must abide in full trust and belief. Butzer expressed his decided assent to the doctrine of objective Presence and presentation; but the actual reception of the Lord's Body, as offered from above, he could only concede to those communicants who, at least through some faith, placed themselves in an inward spiritual relation to that Body and accepted the institution of Christ, not to those who were simply there with their bodies and bodily mouths. To enable one to speak of a partaking of the Body, he was satisfied with that faith which was not exactly the right faith of the heart, and was connected with moral unworthiness, so that such guests ate to their own condemnation. He thus acknowledged that the unworthy, but not the man wholly devoid of faith, could partake of the Body and Blood of Christ. Luther, therefore, could feel assured that Butzer agreed with him in rejecting every view which held that, in the Sacrament, the Body of Christ was present only in the subjective representation and the imagination, or that faith there rose up out of itself, so to speak, to the Lord, instead of merely grasping at what was offered, and thereby being quickened and made strong. But it is unmistakable, that Luther and Butzer conceived in different ways both the manner of the Presence and the manner of partaking,—each of these, indeed, in a mysterious sense and one very difficult to be defined. Luther could scarcely have failed to observe the difference, which still remained between them, and the defect from which, according to his own convictions, the doctrine of the South Germans still suffered. The question was, whether he could look beyond this, and whether in the doctrine for which he had fought so keenly, he should be able and willing to distinguish between what was essential on the one hand, and what was non-essential or less essential on the other.

On the Tuesday all the deputies assembled at his house, together with his Wittenberg friends, and Menius and Myconius. Butzer having spoken on the deputies' behalf, Luther conferred with them separately, and after they had declared their unanimous concurrence with Butzer, he withdrew with his friends into another room for a private consultation. On his return, he declared, on behalf of himself and his friends, that, after having heard from all present their answers and statement of belief, they were agreed with them, and welcomed them as beloved brethren in the Lord. As to the objection they had about the godless partakers, if they confessed that the unworthy received with the other communicants the Body of Christ, they would not quarrel on that point. Luther, so Myconius tells us, spoke these words with great spirit and animation, as was apparent from his eyes and his whole countenance. Capito and Butzer could not refrain from tears. All stood with folded hands and gave thanks to God.

On the following days other points were discussed, such as the significance of infant baptism, and the practice of confession and absolution, as to which an understanding was necessary, and was arrived at without any difficulty. The South Germans had also to be reassured about some individual forms of worship, unimportant in themselves, and which they found to have been retained from Catholic usage in the Saxon churches.

On the Thursday the proceedings were interrupted by the festival of the Ascension. Luther preached the evening sermon of that day on the text, 'Go ye into all the world, and preach the gospel to every creature.' Myconius relates of this sermon, 'I have often heard Luther before, but it seemed to me then as if not he alone were speaking, but heaven was thundering in the name of Christ.'

On Saturday Butzer and Capito delivered themselves of their commissions on behalf of the Swiss. Luther declared after reading the Confession which they brought, that certain expressions in it were objectionable, but added a wish that the Strasburgers would treat with them further the subject, and the latter led him to hope that the communities in Switzerland, weary of dispute, desired unity.

The spirit of brotherly union received a touching and beautiful expression on the Sunday in the common celebration of the Sacrament, and in sermons preached by Alber of Reutlingen in the early morning, and by Butzer in the middle of the day.