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.
Austro-Italian ironclad arms race
After the failure of the First Italian War of Independence, Sardinia began the search for potential allies. Sardinian Prime Minister Camillo Benso, Count of Cavour, found French Emperor Napoleon III supportive of an alliance with Sardinia following the Crimean War, in which France and Sardinia were allies against Russia. After the Plombières Agreement of 1858, Napoleon III and Cavour signed a secret treaty of alliance against Austria whereby France would assist Sardinia in return for Nice and Savoy being ceded to France. The Franco-Sardinian forces quickly defeated the Austrians during the spring of 1859 and after the Battle of Solferino, Austria ceded most of Lombardy and the city of Milan to France under the Treaty of Zürich, who transferred it to Sardinia in exchange for Savoy and Nice. During the war, Italian revolutionary Giuseppe Garibaldi would emerge as a leader for the unification of Italy. Garibaldi, initially supported a republican revolution to bring the peninsula together. However, he eventually concluded that only the Kingdom of Sardinia could unify the Italian states into one nation.