In one brilliant campaign he drove the Venetians back beyond the Adda, burned their fleet at Casal Maggiore on the Po, and utterly defeated their army at Caravaggio.

Then he returned as conqueror to Milan, reduced the surrounding cities, blockaded the Milanese in their capital, and forced them to receive him as their Duke in 1450.

Italy had lost a noble opportunity.

If Florence and Venice had but taken part with Milan, and had stimulated the flagging energies of Genoa, four powerful republics in federation might have maintained the freedom of the whole peninsula and have resisted foreign interference.

But Cosimo de' Medici, who was silently founding the despotism of his own family in Florence, preferred to see a duke in Milan; and Venice, guided by the Doge Francesco Foscari, thought only of territorial aggrandizement.