Sancho IV (Sancho the Brave), 1257?-1295, Spanish king of Castile and León (1284–95), son and successor of Alfonso X. On the death (1275) of his elder brother, Ferdinand de la Cerda, Sancho was designated as Alfonso's successor by a coalition of nobles. Throughout his reign Sancho was forced to defend his throne against the claims of Ferdinand de la Cerda's heirs, who at times received the support of Aragón. He conquered (1292) Tarifa from the Moors. His son, Ferdinand IV, succeeded him under the regency of Sancho's widow, María de Molina.