As a great banker, Cosimo de’ Medici was an important personage in many foreign courts, quite apart from his [Sidenote: Cosimo’s Foreign Policy.] political position in Florence. With very notable dexterity he played his two parts so as to make each improve the other. He employed his financial relations to strengthen his hold upon the strings of Florentine policy, and he utilised his political influence to increase his business and his profits. It is in foreign affairs far more than in domestic administration that he showed himself to be the real ruler of Florence. He inherited from the Albizzi a struggle against Filippo Maria Visconti and an alliance with Venice. As long as the duke of Milan threatened the independence of Florence, and especially when he espoused the cause of the exiled Albizzi, Cosimo could not safely depart from the traditional policy of Florence. But the death of Filippo Maria in 1447 and the establishment of a republic in Milan gave him more scope for originality. He had to choose between the aggrandisement of Venice in Lombardy, which must have been the inevitable result of the maintenance of the Milanese republic, and the erection of a military power in Milan which should hold Venice in check. Without any hesitation he decided for the latter alternative, and the later history of Italy was vitally influenced by his choice. The financial and other aid which he received from Florence was one of the most potent factors in enabling Francesco Sforza to obtain the lordship of Milan in 1450, and to conclude the treaty of Lodi with Venice in 1454. Another hardly less momentous question for Italy arose after the death of Alfonso V. of Naples, when in 1460 the Angevin claim was revived in antagonism to Ferrante. Although Florence was closely allied with France by her Guelf traditions and her commercial interests, Cosimo was resolute in his support of Ferrante and in urging Francesco Sforza to do the same. Again his attitude helped to turn the scale in a struggle where, for a time, the balance was undecided. He just lived to hear of the retirement of John of Calabria, which secured the bastard house of Aragon from serious attack for the next thirty years. By his action in these two great crises Cosimo must be regarded as the real author of that triple alliance between Naples, Milan, and Florence, of which his grandson in later years made such a masterly use.