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.
Flag of Sardinia
Before the Kingdom of Sardinia was founded, the rulers of the island were known as archons (ἄρχοντες in Greek) or judges ("iudices" in Latin, "judikes" in Sardinian, "giudici" in Italian). The island was organized into one "judicatus" from the 9th century on (see List of monarchs of Sardinia). After the Muslim conquest of Sicily in the 9th century, the Byzantines, who previously ruled Sardinia, couldn't manage to defend their far west province. Probably, a local noble family acceded to power, still identifying themselves as vassal of the Byzantines, but independent "de facto", as communications with Constantinople were very difficult. At the beginnings of the 11th century an attempt to conquer the island was made by Spanish Muslims. We have very little record of that war, only by Pisa and Genoa chronicles. Christians won, but after that, the previous Sardinian kingdom was totally undermined and divided into four more little judicati: Cagliari, Arborea, Gallura, and Torres or Logudoro; each one developed its own coat of arms. When, with the appointment of the King of Aragon as King of Sardinia, the island again became one united kingdom, only the Judicatus of Arborea survived, and fought for a century against the Kingdom of Sardinia for supremacy.