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.
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.