Medieval

After the fall of the Western Roman Empire in 476, Italy became a contested territory rather than a unified state. The Ostrogoths ruled most of the peninsula while preserving many Roman structures, but Justinian’s Byzantine armies invaded in the 530s to reassert imperial control. The prolonged Gothic War devastated Italy and left it divided: the Byzantines held key coastal and administrative centers such as Ravenna, Rome, Naples, and parts of the south, while the Lombards, arriving in 568, established a network of duchies across the north and center. This division between Byzantine enclaves and Lombard domains shaped Italian politics for the next two centuries.

A new configuration emerged in the late 8th century when Charlemagne’s Franks defeated the Lombards and incorporated northern and central Italy into the Carolingian empire. The papacy, seeking protection from both Lombards and Byzantines, aligned with the Franks and gradually built its own territorial base, forming the early Papal States. After the Carolingian empire fractured in the 9th century, central authority weakened. Local counts, bishops, and aristocratic families asserted control, and the title “king of Italy” became contested among German and Italian nobles, drawing in the rulers of East Francia, who later became Holy Roman Emperors.

By the 11th and 12th centuries, many northern and central Italian cities turned this fragmentation into self-government. Milan, Florence, Genoa, Venice, and others developed communal regimes dominated by merchant elites and financed through trade, banking, and manufacturing. Their autonomy brought them into recurring conflict with the Holy Roman Emperors, producing the long Guelph–Ghibelline divide between pro-papal and pro-imperial factions. In the south, a separate consolidation occurred as Norman adventurers captured Byzantine and Muslim territories in southern Italy and Sicily, forming a centralized kingdom that later passed to the Hohenstaufen and Angevin dynasties.

By the later Middle Ages, Italy consisted of powerful city-states, territorial principalities, and the Papal States. Florence, Venice, and Milan controlled substantial regional domains; the papacy solidified its authority in central Italy; and Sicily and Naples remained under successive foreign dynasties. This political configuration, though competitive and unstable, produced the economic strength and urban development that set the conditions for the Italian Renaissance in the 14th and 15th centuries.

Unification

Process by which Piedmont-Sardinia incorporated the Italian states into a single kingdom between 1859 and 1871. After 1815, Austria ruled Lombardy and Venetia and controlled several central duchies, while the Papal States and the Bourbon Kingdom of the Two Sicilies remained independent. Piedmont-Sardinia was the only state positioned to change this order because it had a constitutional government, a modern army, and a leadership committed to removing Austria through foreign alliances.

In 1859 Cavour, Piedmont’s prime minister, secured the support of Napoleon III of France and used it to provoke a war with Austria. The Franco-Piedmontese victory forced Austria to surrender Lombardy. This shift in power triggered revolutions in Tuscany, Parma, Modena, and Romagna, where local governments were deposed and votes produced large majorities for annexation to Piedmont. These acquisitions created a continuous Piedmontese-controlled territory from the Alps to the Papal States. Mazzini’s earlier republican activism had built national sentiment, but it was Piedmont’s statecraft that converted it into territorial unification.

In 1860 Garibaldi opened the southern phase of unification. Leading a volunteer force of about a thousand men, he captured Sicily and advanced through the mainland south, collapsing Bourbon rule. His progress raised the possibility of a separate republican regime. Cavour responded by sending Piedmontese forces south to control the political outcome. Garibaldi handed all conquered territory to King Victor Emmanuel II (monarch of Piedmont-Sardinia), allowing the Kingdom of Italy to be proclaimed in March 1861, with Venetia and Rome added in 1866 and 1870.