 William might be the "Count William Sánchez" who, according to Sampiro, defeated the Vikings in Galicia in 970.No Galiciam of that name is known from the 10th century, but neither is there any other record of William Sánchez travelling to Galicia.It has been proposed, however, that the duke of Gascony was on a pilgrimage to the shrine of Saint James at Compostela when, in an emergency, he took command of the defences during a Viking attack.