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.
Norman conquest of southern Italy
After 250 years of Arab control, Sicily was inhabited by a mix of Christians, Arab Muslims, and Muslim converts at the time of its conquest by the Normans. Arab Sicily had a thriving trade network with the Mediterranean world, and was known in the Arab world as a luxurious & decadent place. It had originally been under the rule of the Aghlabids and then the Fatimids, but in 948 the Kalbids wrested control of the island and held it until 1053. During the 1010s and 1020s, a series of succession crises paved the way for interference by the Zirids of Ifriqiya. Sicily was racked by turmoil as petty fiefdoms battled each other for supremacy. Into this, the Normans under Robert Guiscard and his younger brother Roger Bosso came intending to conquer; the pope had conferred on Robert the title of "Duke of Sicily", encouraging him to seize Sicily from the Saracens.