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.
France–Italy relations
The border between France and Savoy had remained in flux since the Italian Wars. In the early modern period, it was fixed in the Treaty of Turin of 1696. After the War of the Spanish Succession, the House of Savoy made large territorial gains, becoming the 18th-century nucleus for the later Italian unification. Savoy was occupied by revolutionary France from 1792 to 1815. Savoy, along with Piedmont and Nice, was conjoined into the Kingdom of Sardinia at the Congress of Vienna in 1815, In 1860, under the terms of the Treaty of Turin, Savoie and Nice was annexed by France, while Lombardy passed to Italy. The last Duke of Savoy, Victor Emmanuel II, became King of Italy.