Leo X. was constantly engaged with the crusade he had preached. He consulted with able captains, and acquired information concerning the strength of the Turks, and upon the means of attacking them with advantage: the most certain means was to raise numerous armies. In his letters to the princes and the faithful, he exhorted Christians not to neglect prayers and the austerities of penitence; but he recommended them above all things to prepare their arms, and to oppose their redoubtable enemies with strength and valour. In concert with the principal states of Christendom, he laid down the plan of the holy war. The emperor of Germany was to furnish an army to which the Hungarian and Polish cavalry should be united. The king of France, with all his forces, all those of the Venetians, and several states of Italy, and sixteen thousand Swiss, was to embark at Brindisi, and make a descent upon the coast of Greece; whilst the fleets of Spain, Portugal, and England, should set sail from Carthagena and the neighbouring ports, to transport Spanish troops to the shores of the Hellespont. The pope proposed to embark himself at the port of Ancona, to repair to Constantinople, under the walls of which city all the forces of the Christian powers were to meet. This plan was gigantic, and never would the Ottoman empire have been in greater danger, if such vast designs could have been carried into execution. But the Christian monarchs were only able to observe the truce proclaimed by the pope, and which they had accepted for a very few months; each of them had engaged to furnish for the crusade troops which every day became more necessary to them in their own states, and which they wished to aggrandize or defend. The old age of Maximilian, and the approaching vacancy of the imperial throne, at that time held all the ambitious in a state of expectation: very shortly the rivalry of Charles V. and Francis I. rekindled war in Europe, and Christendom, disturbed by the quarrels of princes, no longer thought it probable they should be invaded by the Turks.