Sancho of Alburquerque
(1342 - 1375) is known in Spanish
as Sancho de Castilla, Infante de Castilla, 1. Conde de Alburquerque
He was the ninth of the ten illegitimate children of King Alfonso XI of Castile and Lady Eleanor of Guzman.
He was born in Seville. He participated in a revolt of the Castilian nobles against the despotic rule of his brother Pedro of Castile.
In 1373 he married Beatrice of Portugal, daughter of Peter I of Portugal and Ines de Castro. They had two children: Fernando Sanchez, 2nd Count of Alburquerque, and Eleanor of Alburquerque, who married Ferdinand I of Aragon.
He also had an illegitimate daughter, Eleanor Sanchez of Castile.