In the early 1480s, Duke Ercole of Este and Ferrara foolishly began to provoke Venice on a variety of economic and political issues, perhaps deeming Venice to be temporarily powerless because of recent severe losses to the Ottoman Turks in the Eastern Mediterranean. At the same time, King Ferdinand of Naples--Duke Ercole's father-in-law--was in a struggle with Pope Sixtus IV and the Papal States. The Pope and Venice entered an alliance against their respective foes, with Ferrara designated to be Venice's prize. In the Fall of 1481 the mercenary army of Venice launched a remarkably successful land offensive against Duke Ercole's forces while her fleet attacked the ships and port towns of Naples.

The dimensions of Venice's victories soon tempered the Pope's enthusiasm, however. When Milan and Florence allied themselves with Duke Ercole and Naples in order to check Venice's further territorial expansion, the Pope reversed field entirely, calling for Venice to cease hostilities. Peace finally returned in August 1484 with a treaty signed at Bagnolo.

The peace did not bring Venice the prize she had sought--Ferrara--but she did acquire the town of Rovigo and a broad fertile area of the Po River delta known as the Polesine.

Unfortunately, Venice failed to draw a lesson from the remarkably broad alliance that her continued territorial expansion had provoked among her normally fractious neighbors of the Italian peninsula. Within 15 years her actions would bring about a renewal of that alliance, but strengthened by the addition of major powers outside the peninsula as well--with disastrous results.