Calvin's presence at these religious congresses was not devoid of pleasure and valuable result to himself. He was brought into personal relation with almost all of the most eminent men in the different reformed churches; and he soon obtained such a high place in their esteem that with one consent they called him _The Theologian_, being struck not only by the extent of his knowledge, but by the clear insight and courage which he displayed, in dealing with the difficult questions which they had to discuss. There was one important meeting--perhaps the most important of any for the Reformation--which did not, however, take place at these conferences--Calvin did not meet Luther; the two great reformers never once saw each other and talked together. Calvin, no doubt, regretted it keenly, for he ardently desired the unity of the reformed churches. He wrote to the learned Bullinger of Zurich: 'Nothing is more important, not only for us but for the whole Christian Church, than the maintenance of true harmony between those men to whom the Lord has confided great powers. This is the point on which Satan has fixed his eyes; he desires nothing so much as to excite quarrels among us, and to isolate us from each other.' {242} Calvin was especially troubled at the controversy between Luther and Zwingli on the subject of the eucharist: 'Although I have the highest opinion of Luther's piety,' he wrote to his friend Bucer, 'I do not really know what I ought to think of him; even his friends acknowledge that there is a good dose of self-esteem in his firmness, and it does not seem to me at all improbable. The Swiss may therefore be excused if they distrust the attempts at re-union; Luther's offensive pride compels them to do so.' A message, and a few words uttered by Luther, modified these impressions. Calvin wrote to Farel: 'Craton, one of our engravers, has just come from Wittenberg; he has brought a letter from Luther to Bucer, in which Luther says, "Greet Calvin--whose little works I have read with remarkable pleasure-- affectionately." Philip (Melancthon) also writes: "Calvin is in high favour here." He also desired the messenger to say that certain persons, wishing to irritate Martin (Luther), had pointed out several passages in my works in which I alluded to him and his followers in very bitter terms. Luther examined the passages, and saw that he was undoubtedly the person referred to; he ended by saying, "I hope Calvin will think better of me one day; we ought to bear with something from so excellent a man." If we are not melted by so much gentleness,' adds Calvin, 'we must be stones; as for me, I am melted.' {243}