Victor Emmanuel II in the context of "Italian unification"

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.

Giuseppe Maria Garibaldi (/ˌɡærɪˈbɑːldi/ GARR-ib-AHL-dee, Italian: [dʒuˈzɛppe ɡariˈbaldi] ; 4 July 1807 – 2 June 1882) was an Italian general, revolutionary and republican. He contributed to the Unification of Italy (Risorgimento) and the creation of the Kingdom of Italy. He is considered to be one of Italy's "fathers of the fatherland", along with Camillo Benso di Cavour, King Victor Emmanuel II and Giuseppe Mazzini. Garibaldi is also known as the "Hero of the Two Worlds" because of his military enterprises in South America and Europe.

Garibaldi was a follower of the Italian nationalist Mazzini and embraced the republican nationalism of the Young Italy movement. He became a supporter of Italian unification under a democratic republican government. However, breaking with Mazzini, he pragmatically allied himself with the monarchist Cavour and Kingdom of Sardinia in the struggle for independence, subordinating his republican ideals to his nationalist ones until Italy was unified. After participating in an uprising in Piedmont, he was sentenced to death, but escaped and sailed to South America, where he spent 14 years in exile, during which he took part in several wars and learned the art of guerrilla warfare. In 1835 he joined the rebels known as the Ragamuffins (farrapos), in the Ragamuffin War in Brazil, and took up their cause of establishing the Riograndense Republic and later the Catarinense Republic. Garibaldi also became involved in the Uruguayan Civil War, raising an Italian force known as Redshirts, and is still celebrated as an important contributor to Uruguay's reconstitution.

The Kingdom of Italy was proclaimed with a normative act of the Savoyard Kingdom of Sardinia — the law 17 March 1861, n. 4761 — with which Victor Emmanuel II assumed for himself and for his successors the title of King of Italy. 17 March is commemorated annually by the anniversary of the unification of Italy, a national holiday established in 1911 on the occasion of the 50th anniversary, and also celebrated, in the Republican era, in 1961 and 2011.

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.

The House of Savoy (Italian: Casa Savoia, French: Maison de Savoie) is a royal house (formally a dynasty) of Franco-Italian origin that was established in 1003 in the historical region of Savoy, which was originally part of the Kingdom of Burgundy and now lies mostly within southeastern France. Through gradual expansions, the family grew in power, first ruling the County of Savoy, a small Alpine county northwest of Italy, and later gaining absolute rule of the Kingdom of Sicily. During the years 1713 to 1720, they were handed the Kingdom of Sardinia and would exercise direct rule from then onward as Piedmont–Sardinia, which was the legal predecessor state of the Kingdom of Italy and the Italian Empire, which in turn are the predecessors of the present-day Italian Republic.

From rule of a region on the French–Italian border, by the time of the abolition of monarchy in Italy, the dynasty's realm grew to include nearly all of the Italian peninsula. Through its junior branch of Savoy-Carignano, the House of Savoy led the Italian unification in 1861, and ruled the Kingdom of Italy until 1946. They also briefly ruled the Kingdom of Spain during the 19th century. The Savoyard kings of Italy were Victor Emmanuel II, Umberto I, Victor Emmanuel III, and Umberto II. Umberto II reigned for only a few weeks, as the last king of Italy, before being deposed following the 1946 Italian institutional referendum, after which the Italian Republic was proclaimed.

Umberto I (Italian: Umberto Ranieri Carlo Emanuele Giovanni Maria Ferdinando Eugenio di Savoia; 14 March 1844 – 29 July 1900) was King of Italy from 9 January 1878 until his assassination in 1900. His reign saw the creation of the Italian Empire, as well as the creation of the Triple Alliance among Italy, Germany, and Austria-Hungary.

The son of Victor Emmanuel II and Adelaide of Austria, Umberto took part in the Italian Wars of Independence as a commander of the Royal Sardinian Army. He assumed the Italian throne in 1878 on the death of his father. A strong militarist, Umberto approved the alliance with Germany and Austria-Hungary, which was formalised in 1882. He also encouraged Italy's colonial efforts and oversaw the incorporation of Eritrea and Somalia into the Italian Empire.