Kingdom of Sardinia
On 17 March 1861, law no. 4671 of the Sardinian Parliament proclaimed the Kingdom of Italy, so ratifying the annexations of all other Apennine states, plus Sicily, to the Kingdom of Sardinia. The institutions and laws of the Kingdom were quickly extended to all of Italy, abolishing the administrations of the other regions. Piedmont became the most dominant and wealthiest region in Italy and the capital of Piedmont, Turin, remained the Italian capital until 1865, when the capital was moved to Florence. But many revolts exploded throughout the peninsula, especially in southern Italy, and on the island of Sicily, because of the perceived unfair treatment of the south by the Piedmontese ruling class. The House of Savoy ruled Italy until 1946 when Italy was declared a republic by referendum. In this referendum the southern regions, including Sardinia, voted overwhelmingly in favor of the House of Savoy, with the results being 63.8% in favor of maintaining the monarchy.
Kingdom of Sardinia
The kingdom initially consisted of the islands of Corsica and Sardinia, sovereignty over both of which was claimed by the Papacy, which granted them as a fief, the "regnum Sardiniae et Corsicae" ("kingdom of Sardinia and Corsica"), to King James II of Aragon in 1297. Beginning in 1324, James and his successors conquered the island of Sardinia and established "de facto" their "de jure" authority. In 1420, after the Sardinian-Catalan War, the last competing claim to the island was bought out. After the union of the crowns of Aragon and Castile, Sardinia became a part of the burgeoning Spanish Empire. In 1720 it was ceded by the Habsburg and Bourbon claimants to the Spanish throne to Duke Victor Amadeus II of Savoy. The Kingdom of Sardinia came to be progressively identified with the states ruled by the main branch of the House of Savoy, which included, besides Savoy and Aosta, dynastic possessions since the 11th century, the Principality of Piedmont (a possession built up in the 13th century), and the County of Nice (a possession since 1388). While in theory the traditional capital of the island of Sardinia and seat of its viceroys was Cagliari, the Piedmontese city of Turin was the "de facto" capital of Savoy.