Sancho Alfonso, 1st Count of Alburquerque

Sancho Alfonso of Castile (1342–1374), known in Spanish as Don Sancho Alfonso de Castilla, was Infante of Castile, 1st Count of Alburquerque.

He was born in Seville as the ninth of the ten illegitimate children of Alfonso XI of Castile and Leonor de Guzmán.

He participated in a revolt of the Castilian nobles against the despotic rule of his brother, Peter of Castile. Together with his brothers Henry (future Henry II of Castile), Fadrique and Tello, Sancho fought against his half-brother Peter.

In April 1366, his brother Henry named him Count of Alburquerque, lord of Ledesma, Alba de Liste, Medellín, Tiedra and Montalbán. These lands had been confiscated from the only son of João Afonso de Albuquerque and 7th Lord of Alburquerque. In 1373, Sancho married Beatrice of Portugal, daughter of Peter I of Portugal and Inês de Castro. They had one daughter: Eleanor of Alburquerque, who married Ferdinand I of Aragon.

He also had an illegitimate daughter, boxstyle_1=background-color: #fcc; boxstyle_2=background-color: #fb9; boxstyle_3=background-color: #ffc; boxstyle_4=background-color: #bfc; boxstyle_5=background-color: #9fe; 1= 1. Sancho Alfonso 2= 2. Alfonso XI of Castile 3= 3. Leonor de Guzmán 4= 4. Ferdinand IV of Castile 5= 5. Constance of Portugal 6= 6. Pedro Núñez de Guzmán 7= 7. Juana Ponce de León 8= 8. Sancho IV of Castile 9= 9. María de Molina 10= 10. Denis, King of Portugal 11= 11. Elizabeth of Aragon 12= 12. Álvar Pérez de Guzmán 13= 13. María González Girón 14= 14. Fernán Pérez Ponce de León 15= 15. Urraca Gutiérrez de Meneses