Lombardy remained tranquil under the rule of Francesco Sforza, and Tuscany under that of the Casa Medici.

The kingdom of Naples, conquered by Alfonso of Aragon in 1442, was equally ruled in the spirit of enlightened despotism, while Venice, who had so long formed a state apart, by her recent acquisition of a domain on terra firma, entered the community of Italian politics.

Thus the country had finally resolved itself into five grand constituent elements--the Duchy of Milan, the Republic of S.Mark, Florence, Rome, and the kingdom of Naples--all of them, though widely differing in previous history and constitutional peculiarities, now animated by a common spirit.[2] Politically they tended to despotism; for though Venice continued to be a republic, the government of the Venetian oligarchy was but despotism put into commission.
Intellectually, the same enthusiasm for classical studies, the same artistic energy, and the same impulse to revive Italian literature brought the several centers of the nation into keener sympathy than they had felt before.

A network of diplomacy embraced the cities; and round the leaders of the confederation were grouped inferior burghs, republican or tyrannical as the case might be, like satellites around the luminaries of a solar system.

When Constantinople was taken by the Turks in 1453, Italy felt the need of suppressing her old jealousies, and Nicholas V.induced the four great powers to sign with him a treaty of peace and amity.