There was an ultimate argument in the relations of the Medici with France. The revival of the Angevin claim was a perpetual nightmare to Ferrante and his son, and it might well prove that the house of Aragon would find in a Florentine alliance a substantial bulwark to their throne. At all events, whether hazardous or not, the enterprise was successful. Lorenzo returned to Florence in 1480 with a treaty of [Sidenote: Conclusion of peace, 1480.] peace. It was not, of course, a very glorious agreement: the southern districts of Florentine territory were ceded to Siena, the allies in Romagna were left at the mercy of the Pope, and there was no provision for the restoration of the northern fortress of Sarzana, which had been seized during the war by the Fregosi of Genoa. But anything was better than the continuance of the war, and Lorenzo was hailed as the saviour of the state. It is true that there was a momentary reaction, when it was found that the Neapolitan forces were in no hurry to quit Tuscany, and that Alfonso was apparently taking advantage of party feuds in Siena to maintain a permanent foothold in the province. But the Turks intervened to checkmate any such design, and the occupation of Otranto compelled Alfonso and his troops to retire for the defence of their own territory. Even the obstinate Pope was forced to give way by the danger from the infidel. Sixtus ceased to insist that Lorenzo should make another more humiliating, and perhaps more perilous journey to Rome, and withdrew the interdict which he had launched against Florence for venturing to punish ecclesiastics for a flagrant crime.