All those who in Europe took an interest in the crusade, had, at this time, their eyes directed toward the kingdom of Naples, where Charles of Anjou was making great preparations to accompany his brother into the East; but this kingdom, recently conquered, was doomed again to be the theatre of a war kindled by vengeance and ambition. There fell out in the states of Naples and Sicily, which had so often changed masters, that which almost always takes place after a revolution: deceived hopes were changed into hatreds; the excesses inseparable from a conquest, the presence of an army proud of its victories, with the too violent government of Charles, animated the people against their new King. Clement IV thought it his duty to give a timely and salutary warning. "Your kingdom," he wrote to him, "at first exhausted by the agents of your authority, is now torn by your enemies; thus the caterpillar destroys what has escaped the grasshopper. The kingdom of Sicily and Naples has not been wanting in men to desolate it; where now are they that will defend it?" This letter of the Pope's announced storms ready to break forth. Many of those who had called Charles to the throne regretted the house of Swabia, and directed their new hopes toward Italy, strengthening Conradin, heir of Frederick and of Conrad. This young Prince quitted Germany with an army and advanced toward Italy, strengthening himself in his march with the party of the Ghibellines, and with all those whom the domination of Charles had irritated. All Italy was in flames, and the Pope, Charles' protector, retired to Viterbo, had no defence to afford him, except only the thunders of the Church. Charles of Anjou, however, now assembled his troops, and marched out to meet his rival. The two armies met in the plain of St. Valentine, near Aquila; the army of Conradin was cut to pieces, and the young Prince fell into the power of the conqueror. Posterity cannot pardon Charles for having abused his victory here so far as to condemn and decapitate his disarmed and vanquished enemy. After this execution, Sicily and the country of Naples were given up to all the furies of a jealous, suspicious tyranny, for violence produces violence, and great political crimes never come alone. It was thus that Charles got ready for the crusade; but, on the other hand, Providence was preparing terrible catastrophes for him. "So true it is," says a historian, "that God as often gives kingdoms to punish those he elevates as to chastise those whom he brings low."