The wars in Lombardy, a series of conflicts fought in central-northern Italy between the Republic of Venice and the Duchy of Milan, and their different allies, last from 1425 until the signing of the Treaty of Lodi in 1454.

During their course, the political structure of Italy is transformed: out of a competitive congeries of communes and city-states, emerge the five major Italian territorial powers that are to make up the map of Italy until the Italian Wars.

Important cultural centers of Tuscany and Northern Italy—Siena, Pisa, Urbino, Mantua, Ferrara—become politically marginalized.

The wars, fought in four campaigns, are a struggle for hegemony in Northern Italy that ravages the economy of Lombardy and weakens the power of Venice, whose leaders fail to heed the words of warning in doge Tommaso Mocenigo's famous farewell letter (1423): "Beware of the desire to take what belongs to others, and of making unjust war, for God will destroy you.

"The war, which is both a result and cause of Venetian involvement in the power politics of mainland Italy, finds Venetian territory extended to the banks of the Adda and involves the rest of Italy in shifting alliances but only minor skirmishing.

The shifting counterweight in the balance is the allegiance of Florence, at first allied with Venice against encroachments by Visconti Milan, then switching to ally with Francesco Sforza against the increasing territorial threat of Venice.

The Peace of Lodi, concluded in 1454, brings forty years of comparative peace to Northern Italy, as Venetian conflicts focus elsewhere.