king of Spain from Nov. 16, 1870, until his abdication on Feb. 11, 1873, after which the first Spanish republic was proclaimed.

The second son of the future King Victor Emmanuel II of Sardinia-Piedmont (later, of Italy), he was originally called Amadeus I, duke of Aosta. His candidacy for the Spanish throne (vacant after the deposition of Isabella II in September 1868) was supported by Juan Prim (Prim, Juan), the Spanish prime minister, and Francisco Serrano, the regent. It was opposed by adherents of Isabella's son Alfonso de Borbón (later King Alfonso XII) and advocates of a republic. Elected king by the Cortes (parliament), Amadeus arrived in Spain on Dec. 30, 1870, the day on which Prim died from an assassin's attack. Bereft of Prim's help and feebly served by a series of short-lived ministries, Amadeus faced continuous turmoil. Support for Alfonso increased, along with republican agitation, and the Second Carlist War (1872–76) broke out. As soon as circumstances permitted, Amadeus abdicated gracefully and returned to Italy.