Amadeo I (Italian Amedeo, sometimes anglicized as Amadeus) was the only King of Spain from the House of Savoy. He was the second son of King Vittorio Emanuele II of Italy and was known for most of his life as the Duke of Aosta, but reigned briefly as King of Spain from 1870 to 1873.
He was elected by the Cortes as Spain's monarch in 1870, following the deposition of Isabella II, and sworn in the following year. Amadeo's reign was fraught with growing republicanism, Carlist rebellions in the north, and the Cuban independence movement. He abdicated and returned to Italy in 1873, and the First Spanish Republic was declared as a result.