Sancho IV of Castile

Sancho IV, called the Brave (1258–1295), was the second son of Alfonso X of Castile. After his elder brother Ferdinand de la Cerda died in 1275, Sancho contested the succession against Ferdinand's infant son Alfonso; backed by nobles, he rebelled in 1282 and was crowned at Toledo after his father's death in 1284.

He married María de Molina in 1282 without papal dispensation. He crushed repeated revolts, executing the lord of Biscay, Lope Díaz de Haro, and imprisoning his brother John.

After his release, John rebelled again and brought in the Marinids; in 1291 Sancho relieved Tarifa, where Guzmán the Good had resisted their siege. He died in 1295, leaving María as regent for his nine-year-old son Ferdinand IV.