The Growth of Nationalism in Italy (1815-1871)

The Post-Napoleonic Restoration and the Carbonari (1815–1821)

Following the defeat of Napoleon, the Congress of Vienna returned Italy to a patchwork of separate states, largely under Austrian control or influence. This helped lay the foundation for demands of unification.
The secret society of the Carbonari played a key role in early attempts at revolt against these foreign regimes. Their failed uprisings in 1820-21 nevertheless helped to spread nationalist sentiment.

Giuseppe Mazzini founded the Young Italy movement in 1831, advocating for a united, democratic Italian state. His ideas greatly influenced the younger generation of revolutionary nationalists.
The 1848 revolutions saw uprisings in many Italian states, with Mazzini establishing a temporary Roman Republic in 1849. These revolutions, while ultimately unsuccessful, increased public awareness of unification efforts.

In the Kingdom of Piedmont-Sardinia, under Prime Minister Cavour, a more pragmatic and diplomatic approach to unification was pursued. Cavour sought to modernise the state economically and militarily to challenge Austrian dominance.
The Crimean War (1853–1856) gave Cavour the opportunity to align Piedmont-Sardinia with powerful allies, notably France and Great Britain.
The subsequent wars against Austria (Second Italian War of Independence, 1859) and the expeditions of Garibaldi in southern Italy led to a significant expansion of Piedmont-Sardinian territory, achieving a largely unified Italy by 1861.

After unification in 1861, some territories remained outside the new Kingdom of Italy: notably the Papal States including Rome, and Veneto region under Austrian control.
The Third Italian War of Independence (1866), fought alongside Prussia against Austria, resulted in the acquisition of Veneto.
Rome was finally captured in 1870, during the chaos of the Franco-Prussian War, effectively completing Italian unification and making Rome the capital of a new nation state, Italy.
The importance of nationalism as a driving force should not be underestimated, however, economic factors, international diplomacy, and the actions of key individuals also played significant roles in this process.