هشام المؤيد بالله
Upon the death of the Caliph of Cordoba, Al-Hakam II, in 976, and the succession of his son Hisham II, who had been taught by Al-Mansur Ibn Abi Aamir, the prospects of the Christian kingdoms seemed dim. The troops of Al-Mansur defeated the Christians at Torrevicente, south of Soria. Afterwards, the Muslims returned to triumph at Taracueña, near Osma. In 975, Sancho was defeated by the Moors at San Esteban de Gormaz and it has been suggested that he was captured at the Battle of Estercuel that year.