Francisco Ruiz de Castro y de Sandoval-Rojas (May 1579 - 1637), was a Spanish nobleman and politician the 8th count of Lemos.
Francisco Ruiz de Castro was born in Madrid. His father, Fernando Ruiz de Castro, was Viceroy of Naples from 1599 to 1601 and Francisco succeeded him in the same year. His elder brother Pedro Fernández de Castro, 7th count of Lemos, will be later also Viceroy of Naples in 1610–1616.
Francisco remained in Naples until April 1603. In 1616 he became Viceroy of Sicily, a position he held until 1622. He played an instrumental role in establishing the Orfanotrofio del Buon Pastore in Palermo; a boy's orphanage which eventually evolved into the Palermo Conservatory of Music.[1] [2] In 1629, he became a Benedictine monk at the monastery of San Benito in Sahagun, with the name of Father Agustín de Castro. He died in 1637, and was interred at Monforte de Lemos, Galicia, his family's burial place.