That was the stage in which the Reformation found the whole subject of the Eucharist. Luther early became clear on two points: first, that the celebration of the Eucharist as a repetition of the sacrifice of Christ upon the cross, without any reference whatever to the individual communicant,--indeed, as was oftenest the case, without any lay communicant at all,--was an outrageous violation of every truly Christian conception of the institution, a mere piece of heathen idolatry. But, secondly, Luther still clung to the notion that a something mysterious and miraculous took place when the formula of benediction was duly uttered by the priest, and that this something must still be expressed in terms of the church tradition. "_Hoc est corpus meum_" must have some literal and physical meaning. Especially as he saw the "fanatics," who were not afraid to use their reason and take the consequences, going far ahead of him and repudiating all the mystery of the consecrated symbol, he found himself drawn more and more into sympathy with the traditional view. The Eucharist question thus became the test of distinction not only between Catholic and Protestant but between moderate and radical Protestant as well. Plain men like Landgraf Philip of Hessen, who wanted above all else to see all the forces of Protestantism united in one great assault, were shocked and puzzled to find that men who seemed to them to stand for precisely the same things were held apart by such a mere speculative problem as this. Luther said, and said truly, of his Protestant doctrinal opponents, "these men are of another spirit," and at the Conference of Marburg, in 1529, when the whole future of Protestantism seemed to hang upon the union of the Swiss with the German branch, his personal insistence upon the out-and-out literalness of the Catholic symbol prevented that union forever. He saved the Lutheran Church from the reproach of fanaticism and left the Swiss Church free to follow its more liberal course. That is where the Eucharist question drew near Erasmus. He began to feel the approach of danger and, characteristically, to prepare for it. We have no special treatise on the subject from his hand, though he is said to have written and suppressed two such. His expressions in regard to it are scattered through his apologetic writings. In the "Apology against Certain Spanish Monks," published in 1528, there is a chapter[161] in which he replies to criticism on this point. Here, as everywhere, he tries to draw a clear line between what is essential and what is non-essential to the Christian faith. Hutten, he says, found fault with him because he was not willing to expose himself to all perils for the sake of Luther's doctrine, but he had replied: [161] ix., 1064-1066.