TheHouse of Osorio is an old and influentialSpanish noble family, which originated from theKingdom of Castile.

They descend from countOsorio Martínez, a prominent nobleman in the first half of the 12th century who was member of theFlagínez family and husband to a granddaughter of kingAlfonso VI of León. It was from his grandson, Osorio González, that the family derived itspatronymic surname. His son Rodrigo Osorio is relatively obscure, but had two sons who accompanying kingFerdinand III of Castile on his conquest ofSeville, receiving lands there, and who used Osorio as a surname: Rodrigo Rodríguez Osorio and Álvar Rodríguez Osorio. The son of Rodrigo Rodríguez, also named Álvar Rodríguez Osorio, rose to prominence in the service of kingSancho IV of Castile. He had three sons, Juan Álvarez Osorio, a court official and ancestor of the later noble family, Gonzalo Osorio,Bishop of Mondoñedo (d. 1326), and Álvar Núñez Osorio,Count of Trastámara,Lemos and Sarria, andmayordomo mayor before being executed by kingAlfonso XI in 1329. Later descendants would beGrandees of Spain and would hold numerous titles, includingMarquess of Astorga andDuke of Alburquerque. The Osorio shield is gold with two wolves.^[1]

• J. M. Canal Sánchez-Pagín. "El Conde Osorio Martinez y los Marqueses de Astorga".Astorica 7:11–31 (1988).
• J. de Salazar y Acha. "Los Osorio: Un linaje de más de mil años al servicio de la Corona".Anales de la Real Academia Matritense de Heráldica y Genealogía, 4:143–82 (1996–97).