Duke of Alba (Spanish: Duques de Alba de Tormes) is a Spanish title of nobility accompanied with the dignity Grandee of Spain. In 1472 the title Count of Alba de Tormes, inherited by García Álvarez de Toledo, was elevated to the title Duke of Alba by King Henry IV of Castile.
Duke of Alba de Tormes is one of the main titles of Spain and historically, one of the most powerful families in Europe; which gives its name to the House of Alba. However, it should be borne in mind that three families have succeeded in the Duchy: the original House of Alba or the Álvarez de Toledo, extinct in 1755, the second House of Silva, extinct in 1802, and the third and current House of FitzJames, derived from the illegitimate son of James the VII of Scotland, II of England.
Famous Dukes include Don Fernando Alvarez de Toledo, 3rd Duke of Alba, governor of the Spanish Netherlands (references to "Alba" (Alva in Dutch), particularly in the context of Dutch history, are usually about him); and Doña María del Pilar de Silva, 13th Duchess of Alba, a muse of the painter Francisco Goya.
Dukes married into the families of Christopher Columbus and Cosimo de Medici and the line of the Dukes of Berwick, making them distant relatives of the Earl Spencer and Dukes of Marlborough.