The ultimate victory of Eugenius IV. was assured by the mistakes of his opponents. It only remained for him to [Sidenote: Triumph of Eugenius IV.] complete his triumph by securing the support of the temporal powers of Europe. While he resided in Florence his legates succeeded in restoring the papal supremacy in Rome, and in 1443 he was able once more to return to his capital city. He was careful to avoid the mistakes in Italian politics which had cost him so dear in 1433. Even his arch-opponent, Filippo Maria Visconti, was gained over to his side. The recognition of France was purchased by the countenance which the Pope gave to the Angevin cause in Naples. But when the Neapolitan war ended in the victory of Alfonso of Aragon, Eugenius adroitly changed sides without forfeiting the French allegiance. He had thus put an end to all serious opposition in Italy. England and the Spanish kingdoms took little interest in the schism, and had no motive for supporting Felix V. There remained Germany, which had openly declared for a policy of neutrality. Until the German king and princes could be gained over, the revival of papal authority was incomplete. The task of effecting the reconciliation of Germany was undertaken and accomplished by one man, Æneas Sylvius Piccolomini. The kingship of the Romans was transferred on the death of Sigismund to his son-in-law, Albert of Austria. But Albert died within two years of his elevation, and in 1440 the choice of the electors fell upon another Hapsburg, Frederick _III._, Duke of Styria and Carinthia, and guardian in Austria of Albert’s infant son, Ladislas Postumus. As soon as Frederick had settled family affairs in the east, he came to Germany in 1442 [Sidenote: Reconciliation of Germany to the Roman Pope.] to receive the crown at Aachen and to consider the question of the schism. Envoys from Basel and from Eugenius IV. had already appeared before the German diet, but their exhaustive arguments had not led to any decision, and the neutrality was still observed. In 1442 Frederick III. visited Basel, and there took into his service Æneas Sylvius. The latter was convinced that the cause of Council and Antipope was hopeless, and determined to win his own pardon and advancement by rendering some conspicuous service to Eugenius IV. His diplomacy was as successful as it was unscrupulous. By 1445 he had succeeded in arranging terms between his master and the Pope. Frederick undertook to restore Germany to its obedience to Rome; and Eugenius in return promised to give him the imperial crown, to allow him the nomination to certain bishoprics and benefices, and to grant him a substantial bribe from the ecclesiastical revenues. It was a disgraceful treaty, and in spite of the secrecy with which it was negotiated, it became known that some such agreement was being made. The German princes were indignant at what they considered a betrayal, and were resolute to vindicate their own independence of their elected king.