He was the eldest son of Ordoño II, who inherited Galicia in a partition of the Kingdom of Asturias with his brothers in 910.
[2] He must have reached an agreement with his brother Alfonso, now king in León, since the two of them presided jointly over an assembly of the ecclesiastical and secular magnates of the whole kingdom at Christmas 927.
At this meeting, the royals confirmed the restoration of the Galician monastery of Santa María de Loio by Count Gutier Menéndez and his wife Ilduara.
[1] In charters he issued, Sancho styled himself Prince of Galicia (Gallecie princeps), a title that implied royal rank in the Visigothic tradition, itself borrowed from Roman practice.
[4] In accordance with Visigothic law, she did not remarry after his death but entered the monastery of Santa María in Castrelo de Miño, where she became abbess and was still living in 947.