The conduct of the Landgrave Philip, of Hesse, grieved him exceedingly; for he was very anxious to bring about a union between the Lutherans and the Swiss. For this purpose, he had previously brought about the Conference at Marburg, without, however, accomplishing his purpose in the doctrine of the Lord's Supper. He still entertained thoughts of a union. On this account, Melanchthon wrote to Luther, May 22: "I entreat you most earnestly to write to the Landgrave, and to exhort him, that he should not burden his conscience by defending any false doctrine." In addition to this, Melanchthon and Brenz also addressed a letter to the Landgrave, and justified themselves for not being able to unite with the Zwinglians. The Landgrave replied in very temperate language, insisting upon treating the Zwinglians as brethren, without, however, being able to shake the opinions of the two theologians. The Catholics knew very well that such divisions had arisen in the Evangelical camp. It will always remain a subject of regret that no union could be brought about. Melanchthon and Brenz declared: "We have such articles, of which, by the grace of God, we are certain, and are able to suffer for them with a good conscience, which is indeed a source of great comfort in every danger; but we cannot be certain of the Zwinglian doctrine, as it is called, for we have no clear word of God for it." Relying upon the word of God, they could indeed calmly await coming events. At last the Emperor, who had delayed so long, arrived in Augsburg. He made his public entrance on the 15th of June. Not Cajetan, but the smoother Campegius, accompanied the Emperor, as the Pope's legate. We may well suppose that this public entrance was very magnificent. The following day was the festival of Corpus Christi. As the evangelical princes could not conscientiously take a part in this festival, which celebrated a doctrine which they rejected most decidedly, they took no part in the procession. They declared to the Emperor, who insisted upon their attendance: "They could not conscientiously before God, comply with this demand, because this procession was made a species of worship." The princes at first expressed themselves in the most decided manner, against the Emperor's demand that the preaching should be stopped. The Margrave George even said, before the Emperor: "Rather than deny my God and his Gospel, I would kneel down here before your Imperial Majesty, and have my head cut off." The Emperor replied, in his defective German, "Not head off, not head off." However, as the Emperor had prohibited preaching to both parties, and had reserved the right to appoint preachers for himself, the Lutherans could not complain any longer, especially as their theologians advised peaceful measures. The day preceding the opening of the Diet, Melanchthon wrote to his friend Camerarius, that the Confession would be more moderate than the ungodliness of their enemies deserved.