For three centuries and a half the Mediterranean ceased to be the great highway of commerce, and became merely a considerable inland sea. The marvellous prosperity of Venice ceased with the conditions which had given rise to it. Until the invasion of Charles VIII. brought Venice and Milan once more together, there had been little direct connection between the two states since the treaty of Lodi gave leisure to Francesco Sforza to secure his position [Sidenote: Francesco Sforza in Milan.] in his newly acquired duchy. In this task he was as successful as he had been in the unscrupulous methods by which he rose to power. From the first he determined to sink the _condottiere_ in the prince. Peace, and not war, became the primary object of his policy. With Cosimo de’ Medici he was already on the most friendly terms, and as long as he or his descendants retained their power no opposition was to be feared from Florence. Venice had received a sharp lesson, and her attention was diverted to the east. The popes had enough to do to maintain their recently recovered authority in the papal states. The only other important state in Italy was Naples. As a military leader Sforza had played a prominent part in Neapolitan politics. He had been the champion of the house of Anjou, and when the victory ultimately rested with Alfonso of Aragon, Sforza had been deprived of his estates in Apulia and the Abruzzi. But as duke of Milan, Francesco was eager to be on good terms with the king of Naples. All his interests were now opposed to the Angevin claim on Naples, which might easily be allied with the Orleanist claim to Milan. A double marriage was arranged to cement the alliance between Naples and Milan. Alfonso’s grandson, another Alfonso, was betrothed to Ippolita, Sforza’s daughter, and one of Sforza’s sons was to marry Alfonso’s granddaughter. When Alfonso’s death, in 1458, was followed by a renewed attempt of the Angevins to gain Naples, Sforza gave his cordial support to Ferrante, the natural son of the late king, and materially aided him in defending his throne.