During the late Middle Ages Italy was divided into small city states and kingdoms.Venice and Genoa were Europe's gateways to trade with the East, with the former producer of the renowned venetian glass. Florence was the capital of silk, wool, banks and jewelry. The Maritime Republics were heavily involved in the Crusades, taking advantage of the new political and trading opportunities, most evidently in the conquest of Zara and Constantinople funded by Venice.

During the late Middle Ages Italy was divided into smaller city-states and territories: the kingdom of Naples controlled the south, the Republic of Florence and the Papal States the centre, the Genoese and the Milanese the north and west, and the Venetians the east. Fifteenth-century Italy was one of the most urbanised areas in Europe and the birthplace of Renaissance. Florence in particular, with the writings of Dante Alighieri (1265–1321), Francesco Petrarch (1304–1374) and Giovanni Boccaccio (c. 1313–1375), as well as the painting of Giotto di Bondone (1267–1337), is considered the centre of this cultural movement. Scholars like Niccolò de' Niccoli and Poggio Bracciolini scoured the libraries in search of works of classical authors, such as Plato, Aristotle, Euclid, Ptolemy, Cicero and Vitruvius.

The Black Death pandemic in 1348 left its mark on Italy by killing one third of the population. The recovery from the disaster led to a resurgence of cities, trade and economy which greatly stimulated the successive phases of Humanism and the Renaissance. In 1494 the French king Charles VIII opened the first of a series of invasions, lasting up to sixteenth century, in a competition between France and Spain for the possession of the country. Ultimately Spain prevailed through the Treaty of Cateau-Cambresis which recognised Spanish dominance over the Duchy of Milan and the Kingdom of Naples. The holy alliance between Habsburg Spain and the Holy See resulted in the systematic persecution of any Protestant movement. Austria succeeded Spain as hegemon in Italy under the Peace of Utrecht. Through Austrian domination, the northern part of Italy gained economic dynamism and intellectual fervor. The French Revolution and the Napoleonic Wars (1796–1815) introduced the ideas of equality, democracy, law and nation. Italy’s population between 1700 and 1800 rose by about one-third, to 18 million.

Kingdom of Italy (1861–1946)

Giuseppe Garibaldi leading the Expedition of the Thousand.The creation of the Kingdom of Italy was the result of efforts by Italian nationalists and monarchists loyal to the House of Savoy to establish a united kingdom encompassing the entire Italian Peninsula. In the context of the 1848 liberal revolutions that swept through Europe, an unsuccessful war was declared on Austria. Giuseppe Garibaldi, popular amongst southern Italians, led the Italian republican drive for unification in southern Italy,while the northern Italian monarchy of the Kingdom of Piedmont-Sardinia whose government was led by Camillo Benso, conte di Cavour, had the ambition of establishing a united Italian state under its rule. The kingdom successfully challenged the Austrian Empire in the Second Italian War of Independence with the help of Napoleon III, liberating the Lombardy-Venetia. In 1866, Victor Emmanuel II aligned the kingdom with Prussia during the Austro-Prussian War, waging the Third Italian War of Independence which allowed Italy to annex Venice. In 1870, as France during the disastrous Franco-Prussian War abandoned its positions in Rome, Italy rushed to fill the power gap by taking over the Papal State from French sovereignty. Italian unification finally was achieved, and shortly afterwards Italy's capital was moved to Rome.

As Northern Italy was industrialized and modernized, the south became overcrowded, forcing millions of people to emigrate for a better life abroad. The Sardinian Statuto Albertino of 1848, extended to the whole Kingdom of Italy in 1861, provided for basic freedoms, but the electoral laws excluded the non-propertied and uneducated classes from voting. In 1913, male universal suffrage was adopted. The Socialist Party became the main political party, outclassing the traditional liberal and conservative organisations. Starting from the last two decades of the nineteenth century, Italy developed into a colonial power by forcing Somalia, Eritrea and later Libya and the Dodecanese under its rule. During World War I, Italy at first stayed neutral but in 1915 signed the Treaty of London, entering Entente on the promise of receiving Trento, Trieste, Istria, Dalmatia and parts of Ottoman Empire. During the war, 600,000 Italians died, and the economy collapsed. Under the Peace Treaty of Saint-Germain, Italy obtained just Bolzano-Bozen, Trento, Trieste and Istria in a victory described as "mutilated" by the public.