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 Sicily
Opposition to French officialdom and taxation combined with incitement of rebellion by agents from the Crown of Aragon and the Byzantine Empire led to the successful insurrection of the Sicilian Vespers followed by the invitation and intervention by king Peter III of Aragon in 1282. The resulting War of the Sicilian Vespers lasted until the Peace of Caltabellotta in 1302, dividing the old Kingdom of Sicily in two. The island of Sicily, called the "Kingdom of Sicily beyond the Lighthouse" or the Kingdom of Trinacria, went to Frederick III of the house of Aragon, who had been ruling it. The peninsular territories (the Mezzogiorno), contemporaneously called Kingdom of Sicily but called Kingdom of Naples by modern scholarship, went to Charles II of the house of Anjou, who had likewise been ruling it. Thus, the peace was formal recognition of an uneasy "status quo". The division in the kingdom became permanent in 1372, with the Treaty of Villeneuve. Though the king of Spain was able to seize both crowns in the 16th century, the administrations of the two halves of the Kingdom of Sicily remained separated until 1816, when they were reunited in the Kingdom of Two Sicilies.