In the first half of the 15th century, the larger Italian powers had been consolidating their territories, with Savoy expanding towards the Ligurian coast, Venice focusing on Domini di Terraferma whilst the Stato da Màr were threatened by Turkish expansion, Milan expanding southwards, the Florentines having gained most of Tuscany and the Papal States having begun the unification of the Pontifical territories that would continue over the next two centuries, while Alfonso V, king of Aragon, acquired both Sicilies, reigning the Kingdom of Naples as Alfonso I, as well as expanding to the north. Solemnly proclaimed on the 2 March 1455 with the accession of Pope Nicholas V, king Alfonso and other small states to the League, by it was established a mutual defence agreement and a 25-year truce between the Italian powers, forbidding separate alliances and treaties while committing to maintenance of the established boundaries. After the period of confrontation, the Italian states acknowledged the condottieriFrancesco Sforza as successor to the last of the Visconti of Milan, after having married the only daughter of Filippo Maria Visconti. The relative peace and stability resulting from Lodi and the League, promoted by Sforza, allowed him to consolidate his rule over Milan and it was Cosimo de' Medici's most important foreign policy decision to end the traditional rivalry between his Florence and Sforza's Milan.
Consequences
The League was the coherent development of the Peace of Lodi, born from the realisation that none of the regional Italian states, despite the long and bloody wars in the preceding hundred years, was in a position to assume hegemony in the north, let alone the entire peninsula. The League therefore provided a détente, founded on mutual suspicion and fear of France rather than on collaboration, which might have led to the formation of a broader, unified state. The Italic League played an essential part in the balance of power subsequently pursued by the Florentine ruler Lorenzo de' Medici ; its only cracks were the Pazzi conspiracy, the Barons Conspiracy and the Salt War. The League provided enough stability to allow the peninsular economy to recover from the population loss and economic depression caused by the Black Death and its aftermath, leading to an economic expansion that endured until the first part of the 17th century. The League also enabled the creation of the first permanent embassies amongst the states of the Italian peninsula, in order to monitor compliance with the terms prohibiting supporting exiled dissidents, with De Officio Legati — what seems to be the first treatise on ambassadorship — written by Ermolao Barbaro in Venice in 1490, after he had served the Serenìsima in Burgundy and Milan. With the death of Lorenzo de' Medici in 1492 was marked the decline of the League, he having been one of its greatest supporters and prime maintainer, recognising the advantage of maintaining a balance among the five powers as opposed to trying to eliminate his enemies. Whilst the League failed to prevent the French invasion in 1494 that began the Italian Wars, it did enable the creation of the army that repelled Charles VIII's army after their sack of Naples. The League army engaged the French at Fornovo and retained control of the battlefield but failed to prevent an orderly French retreat. The Venetian alliance with France and Spain against Milan and Naples in the Italian War of 1499–1504, however, sounded the death knell for the League. As a result of the détente, unlike France, Spain and England, Italy failed to coalesce into a nation state in the Middle Ages, and was ripe for conquest by the major European powers. Several factors have been considered causes of this; Francesco Guicciardini blamed particularism, for example, while Niccolò Machiavelli believed it resulted from the moral and civil decay of institutions and morals and in Papal policy, for centuries aimed at avoiding the formation of a unitary Italy. It should be borne in mind, however, that Machiavelli's great work The Prince was a reflection of the political equilibrium resulting from the League's existence.
