Under Sancho, the kingdom solidified some of the gains of his predecessor, but also suffered several significant military setbacks at the hands of Umayyad troops.

It is one of the most important illuminated manuscripts of medieval Spain, containing the canons of the Councils of Toledo, a copy of the Liber Iudiciorum, and the first Western representation of the Arabic numerals, among many other texts.

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.

From this union was born Abd al-Rahman Sanchuelo, the second successor of Al-Mansur who tried to usurp the Caliphate of Córdoba from the Umayyad heir.

He faced further incursions from Almanzor in 989, 991 and 992, the last of which resulted in a second submission at Córdoba, and the next year he sent his son Gonzalo on an embassy to the Caliphate to consolidate the rapprochement.