History of Sardinia
In the Early Middle Ages, through barbarian movements, the waning of the Byzantine Empire influence in the western Mediterranean and the Saracen raids, the island fell out of the sphere of influence of any higher government. This led to the birth of four kingdoms called "Judicates" (Latin: "Judicati"; Sardinian: "Judicados") in the 8th through 10th centuries. Falling under papal influence, Sardinia became the focus of the rivalry of Genoa and Pisa, the Judicates and the Crown of Aragon, which eventually subsumed the island as the Kingdom of Sardinia in 1324. The Kingdom was to last until 1718, when it was ceded to the Piedmontese House of Savoy; later, in 1861, it would thus become the Kingdom of Italy and finally in 1946 the Italian Republic.
Savoy
The territory of Savoy was annexed to France in 1792 under the French First Republic, before being returned to the Kingdom of Sardinia in 1815. Savoy, along with the county of Nice, was finally annexed to France by a plebiscite, under the Second French Empire in 1860, as part of a political agreement (Treaty of Turin) brokered between the French emperor Napoleon III and King Victor Emmanuel II of the Kingdom of Sardinia that began the final steps in the process of unification of Italy. Victor Emmanuel's dynasty, the House of Savoy, retained its Italian lands of Piedmont and Liguria and became the ruling dynasty of Italy.