Kingdom of Sardinia and Aosta, dynastic possessions since the 11th century, the Principality of Piedmont (a possession built up in the 13th century), and the County of Nice (a possession since 1388). While in theory the traditional capital of the island of Sardinia and seat of its viceroys was Cagliari, the Piedmontese city of Turin was the "de facto" capital of Savoy. When the mainland domains of the House of Savoy were occupied and eventually annexed by Napoleonic France, the king of Sardinia made his permanent residence on the island for the first time in its history. The Congress of Vienna (1814–15), which
Kingdom of Sardinia of his son Victor Emmanuel II. In 1852, a liberal ministry under Count Camillo Benso di Cavour was installed and the Kingdom of Sardinia became the engine driving Italian unification. The Kingdom of Sardinia took part in the Crimean War, allied with the Ottoman Empire, Britain, and France, and fighting against Russia. In 1859, France sided with the Kingdom of Sardinia in a war against Austria, the Austro-Sardinian War. Napoleon III did not keep his promises to Cavour to fight until all of the Kingdom of Lombardy-Venetia had been conquered. Following the bloody battles of Magenta and Solferino, both French