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 the Two Sicilies
In 1501, King Ferdinand II of Aragon, son of John II, conquered Naples and reunified the two kingdoms under the authority of the newly united Spanish throne. The Kings of Spain then bore the title "King of Both Sicilies" or "King of Sicily and of the Two Coasts of the Strait" until the War of the Spanish Succession. At the end of that war, the Treaty of Utrecht in 1713 granted Sicily to the Duke of Savoy until the Treaty of Rastatt in 1714 left Naples to the Emperor Charles VI. In 1720 the Emperor and Savoy exchanged Sicily for Sardinia, thus reuniting Naples and Sicily.