Events proved that discontent within Florence was not very formidable, unless it was reinforced by [Sidenote: Foreign policy.] difficulties in foreign relations. Lorenzo had been brought up by his grandfather to regard Milan and Naples as the normal allies of Florence, Venice as a dangerous rival of Florence and a resolute opponent of the Medici ascendency, and the papacy as a variable force depending on the idiosyncracies of rapidly changing popes, and requiring to be very carefully watched. Lorenzo had learned the lesson, but with the egotism and self-sufficiency of youth he was not disinclined to attempt a few experiments on his own account. If he could establish friendly relations with the papacy and with Venice, he might make his own position stronger than ever, and might pose as mediator and almost as arbiter in the relations of the Italian states. On the election of Sixtus IV. in 1471, Lorenzo went in person as Florentine envoy to carry the usual congratulations. He returned not only with a confirmation of his banking privileges in Rome, but with the lucrative appointment of receiver of the papal revenues. At the same time he opened negotiations with Venice, which led in 1474 to the embassy of Tommaso Soderini and the conclusion of an alliance between Venice, Milan, and Florence. But these new connections were dearly purchased by the alienation of Naples. Ferrante regarded Venice as the inveterate enemy of his kingdom and his family. As long as the Medici had identified their interests with his own he had been eager to uphold [Sidenote: Alienation of Naples and quarrel with Sixtus IV.] their power in Florence. But a good understanding of Milan and Florence with Venice threatened Naples with isolation, and Ferrante must seek support elsewhere. Sixtus had already allowed the Neapolitan tribute to be commuted for a formal gift; and as the ties between Naples and the papacy were drawn closer, a coolness grew up between Sixtus and Lorenzo. The origin of the quarrel is to be found in the opposition of Florence to the aggrandisement of Girolamo Riario (see p. 282). Lorenzo refused to find the money for the purchase of Imola, and the Pope transferred the post of receiver-general from the Medici to the Pazzi. The dispute was speedily embittered. Sixtus appointed Francesco Salviati to the archbishopric of Pisa without consulting Lorenzo, and in defiance of his wishes. The Florentines, on their side, refused to admit the archbishop to his see; they supported the Vitelli in Citta di Castello, and in many ways showed an inclination to thwart the Pope’s schemes in Romagna. For some time, however, the dispute did not seem likely to lead to serious results. But the death of Galeazzo Maria Sforza in 1476, and the obvious weakness of the government of the regent, Bona of Savoy, encouraged the opponents of the Medici to bolder acts than they would have contemplated when Milan could give efficient support to Florence. In 1477 Girolamo Riario and