Amadeo I (Italian: Amedeo Ferdinando Maria di Savoia; 30 May 1845 – 18 January 1890), also known as Amadeus, was an Italian prince who reigned as King of Spain from 1870 to 1873. The only king of Spain to come from the House of Savoy, he was the second son of Victor Emmanuel II of Italy and was known for most of his life as the Duke of Aosta, the usual title for a second son in the Savoyard dynasty.
He was elected by the Cortes Generales as Spain's monarch in 1870, following the deposition of Isabel II, and was sworn in the following year. Amadeo's reign was fraught with growing republicanism, Carlist rebellions in the north, and the Cuban independence movement.