Proclamation of the Kingdom of Italy in the context of "Unification of Italy"

The Kingdom of the Two Sicilies (Italian: Regno delle Due Sicilie) was a kingdom in Southern Italy from 1816 to 1861 under the control of the House of Bourbon-Two Sicilies, a cadet branch of the Spanish Bourbons. The kingdom was the largest sovereign state by population and land area in Italy before the Italian unification, comprising Sicily and most of the area of today's Mezzogiorno (southern Italy) and covering all of the Italian peninsula south of the Papal States.

The kingdom was formed when the Kingdom of Sicily merged with the Kingdom of Naples, which was officially also known as the Kingdom of Sicily. Since both kingdoms were named Sicily, they were collectively known as the "Two Sicilies" (Utraque Sicilia, literally "both Sicilies"), and the unified kingdom adopted this name. The king of the Two Sicilies was overthrown by Giuseppe Garibaldi in 1860, after which the people voted in a plebiscite to join the Kingdom of Sardinia. The annexation of the Kingdom of the Two Sicilies completed the first phase of Italian unification, and the new Kingdom of Italy was proclaimed in 1861.

The Kingdom of Sicily (Latin: Regnum Siciliae; Sicilian: Regnu di Sicilia; Italian: Regno di Sicilia) was a state that existed in Sicily and the southern Italian Peninsula as well as, for a time, in Northern Africa, from its founding by Roger II of Sicily in 1130 until 1816. It was a successor state of the County of Sicily, which had been founded in 1071 during the Norman conquest of the southern peninsula. The island was divided into three regions: Val di Mazara, Val Demone and Val di Noto.

After a brief rule by Charles of Anjou, a revolt in 1282 known as the Sicilian Vespers threw off Angevin rule in the island of Sicily. The Angevins managed to maintain control in the mainland part of the kingdom, which became a separate entity also styled Kingdom of Sicily, although it is retroactively referred to as the Kingdom of Naples. The Kingdom of Sicily on the island(also known as Kingdom of Trinacria between 1282 and 1442) on the other hand, remained an independent kingdom ruled by relatives of the House of Barcelona, and was then added permanently to the Crown of Aragon as a result of the Compromise of Caspe of 1412. Following the dynastic union of the crowns of Castile and Aragon in 1479, it was a viceroyalty of the Spanish kingdom. During the War of the Spanish Succession (1700–1714), the island was taken over by the House of Savoy. In 1720, Savoy gave it to Austria in exchange for Sardinia. Later, the island was ruled by a branch of the Bourbons. Following the Napoleonic period, the Kingdom of Sicily was formally merged with the Kingdom of Naples to form the Kingdom of the Two Sicilies, which in 1861 became part of the new unified Kingdom of Italy.

The Unification of Italy (Italian: Unità d'Italia [uniˈta ddiˈtaːlja]), also known as the Risorgimento (Italian: [risordʒiˈmento]; lit. 'Resurgence'), was the 19th century political and social movement that in 1861 ended in the annexation of various states of the Italian peninsula and its outlying isles to the Kingdom of Sardinia, resulting in the creation of the Kingdom of Italy. Inspired by the rebellions in the 1820s and 1830s against the outcome of the Congress of Vienna, the unification process was precipitated by the Revolutions of 1848, and reached completion in 1870 after the capture of Rome and its designation as the capital of the Kingdom of Italy.

Individuals who played a major part in the struggle for unification and liberation from foreign domination included King Victor Emmanuel II; politician, economist and statesman Camillo Benso, Count of Cavour; general Giuseppe Garibaldi; and journalist and politician Giuseppe Mazzini. Borrowing from the old Latin title Pater Patriae of the Roman emperors, the Italians gave to King Victor Emmanuel II the epithet of Father of the Fatherland (Italian: Padre della Patria). Even after 1870, many ethnic Italian-speakers (Italians in Trentino-Alto Adige/Südtirol, Savoyard Italians, Corfiot Italians, Niçard Italians, Swiss Italians, Corsican Italians, Maltese Italians, Istrian Italians, and Dalmatian Italians) remained outside the borders of the Kingdom of Italy, planting the seeds of Italian irredentism.

The Expedition of the Thousand (Italian: Spedizione dei Mille) was an event of the unification of Italy that took place in 1860. A corps of volunteers led by Giuseppe Garibaldi sailed from Quarto al Mare near Genoa and landed in Marsala, Sicily, in order to conquer the Kingdom of the Two Sicilies, ruled by the Spanish House of Bourbon-Two Sicilies. The name of the expedition derives from the initial number of participants, which was around 1,000 people.

The Garibaldians, with the contribution of southern volunteers and reinforcements to the expedition, increased in number, creating the Southern Army. After a campaign of a few months with some victorious battles against the Bourbon army, the Thousand and the newborn southern army managed to conquer the entire Kingdom of the Two Sicilies. The expedition was a success and concluded with a plebiscite that brought Naples and Sicily into the Kingdom of Piedmont-Sardinia, the last territorial conquest before the proclamation of the Kingdom of Italy on 17 March 1861. The Expedition of the Thousand was the only desired action that was jointly decided by the four "Fathers of the Fatherland": Giuseppe Mazzini, Giuseppe Garibaldi, King Victor Emmanuel II, and Camillo Benso, Count of Cavour, pursuing divergent goals. Mazzini, of republican political belief, wanted to liberate Southern Italy and Rome, while Garibaldi wanted to conquer, in the name of Victor Emmanuel II, the Kingdom of the Two Sicilies and continue towards Rome to complete the Italian unification, while Cavour wanted to prevent the conquest of Rome to avoid a conflict with his French ally, Napoleon III, who protected the Papal States.

The Kingdom of Italy (Italian: Regno d'Italia, pronounced [ˈreɲɲo diˈtaːlja]) was a unitary state that existed from 17 March 1861, when Victor Emmanuel II of Sardinia was proclaimed King of Italy, until 10 June 1946, when the monarchy was abolished, following civil discontent that led to an institutional referendum on 2 June 1946. This resulted in a modern Italian Republic. The kingdom was established through the unification of several states over a decades-long process, called the Risorgimento. That process was influenced by the Savoy-led Kingdom of Sardinia, which was one of Italy's legal predecessor states. In 1882 it became a colonial empire, establishing the Italian Empire.

In 1866, Italy declared war on Austria in alliance with Prussia and, upon its victory, received the region of Veneto. Italian troops entered Rome in 1870, ending more than one thousand years of Papal temporal power. In the last two decades of the 19th century, Italy developed into a colonial power, and in 1882 it entered into a Triple Alliance with the German Empire and the Austro-Hungarian Empire, following strong disagreements with France about their respective colonial expansions. Although relations with Berlin became very friendly, the alliance with Vienna remained purely formal, due in part to Italy's desire to acquire Trentino and Trieste from Austria-Hungary. As a result, Italy accepted the British invitation to join the Allied Powers during World War I, as the western powers promised territorial compensation (at the expense of Austria-Hungary) for participation that was more generous than Vienna's offer in exchange for Italian neutrality. Victory in the war gave Italy a permanent seat in the Council of the League of Nations, but it did not receive all the territories it was promised.

Italian nationalism (Italian: Nazionalismo italiano) is a movement which believes that the Italians are a nation with a single homogeneous identity, and therefrom seeks to promote the cultural unity of Italy as a country. From an Italian nationalist perspective, Italianness is defined as claiming cultural and ethnic descent from the Latins, an Italic tribe which originally dwelt in Latium and came to dominate the Italian peninsula and much of Europe. Because of that, Italian nationalism has also historically adhered to imperialist theories.

Italian nationalism is often thought to trace its origins to the Renaissance, but only arose as a political force in the 1830s under the leadership of Giuseppe Mazzini. It served as a cause for Risorgimento in the 1860s to 1870s. Italian nationalism became strong again in World War I with Italian irredentist claims to territories held by Austria-Hungary, and during the era of Italian Fascism.

The Anniversary of the Unification of Italy (Italian: Anniversario dell'Unità d'Italia) is a national day that falls annually on 17 March and celebrates the birth of Italy as a modern nation state, which took place following the proclamation of the Kingdom of Italy on 17 March 1861.

However, the complete unification of Italy took place only in the following years. In 1866 the Veneto and the province of Mantua were annexed after the Third Italian War of Independence, then in 1870 Lazio after the capture of Rome, and finally in 1918 Trentino-Alto Adige and Julian March after the First World War. In this regard, the National Unity and Armed Forces Day (Victory Day) was also established, which is celebrated annually on 4 November, recalling the Italian victory in the First World War, a war event considered to complete the process of unification of Italy.