Venice and Milan came to the support of Florence, whereupon Milan's attentions were diverted to her own affairs, Genoa being cunningly set in revolt against her.
In 1480 a peace was patched up; but it was short-lived.

A few months later war flared out again from the Holy See, against Florence this time, and on the pretext of its having joined the Venetians against the Pope in the late war.

A complication now arose, created by the Venetians, who seized the opportunity to forward their own ambitions and increase their territories on the mainland, and upon a pretext of the pettiest themselves declared war upon Ferrara.

Genoa and some minor tyrannies were drawn into the quarrel on the one side, whilst on the other Florence, Naples, Mantua, Milan, and Bologna stood by Ferrara.
Whilst the papal forces were holding in check the Neapolitans who sought to pass north to aid Ferrara, whilst the Roman Campagna was being harassed by the Colonna, and Milan was engaged with Genoa, the Venetians invested Ferrara, forced her to starvation and to yielding-point.
Thereupon the Pope, perceiving the trend of affairs, and that the only likely profit to be derived from the campaign would lie with Venice, suddenly changed sides that he might avoid a contingency so far removed from all his aims.
He made a treaty with Naples, and permitted the Neapolitan army passage through his territories, of which they availed themselves to convey supplies to Ferrara and neutralize the siege.

At the same time the Pope excommunicated the Venetians, and urged all Italy to make war upon them.
In this fashion the campaign dragged on to every one's disadvantage and without any decisive battle fought, until at last the peace of Bagnolo was concluded in August of 1484, and the opposing armies withdrew from Ferrara.
The news of it literally killed Sixtus.