The pope proposed to levy for the crusade a tenth upon the revenues of the clergy, a twentieth upon the Jews, and a thirtieth upon princes and seculars. He proposed at the same time, to raise an army of a hundred thousand men in the different states of Europe, and to intrust the command of this army to the emperor of Germany. These propositions, in order to be executed, required the approbation of the sovereigns, and most of the ambassadors made only vague promises. A great number of conferences were held; the council lasted many months, and the pope quitted Mantua without having done anything decisive for the enterprise he meditated. He returned to Rome, whence he wrote again to the Christian princes, conjuring them to send ambassadors, to deliberate afresh upon the war against the Turks. Constantly pursued by the thought of delivering the Christian world, and losing hope daily of being able to affect the West, he conceived the strange idea of addressing Mahomet II. himself, and of employing all the powers of reasoning and eloquence to convert the Mussulman prince to Christianity. His letter, which we still possess, presents a complete treatise of the philosophy and the theology of the time. The pontiff opposes to the apostles of Islamism, the authority of the prophets and the fathers of the Church, and the profane authority of Lycurgus and Solon. Aiming particularly at interesting the ambition of the Ottoman emperor, he proposes to him the example of the great Constantine, who obtained the empire of the world on receiving baptism, and investing himself with that sign by which it was given to him to conquer. The sultan had only to acknowledge the God from whom all authority comes, to have the Abyssinians, the Arabs, the Mamelukes, the Persians, with all the nations of Asia, submit to his domination; and if the intercession of the court of Rome were necessary for him to reign over the East, the head of the Church promised him the assistance of his prayers, and the support of the pontifical sovereignty. In this singular negotiation with Mahomet II., the pope was not more fortunate than with the Christian princes. The latter, when he urged them to defend their own states, answered by vain protestations. Mahomet, to whom he offered the conquest of the world, contented himself with replying, that “he was innocent of the death of Jesus Christ, and that he thought with horror of those who had fastened him to the cross.”