 He was either a son of García I or of Centule, a brother of Sancho I.

Lupo was a Gascon rebel against the authority of Pepin in Aquitaine.In 818, the death of García left a power vacuum in Gascony which Lupo attempted to fill.Pepin responded quickly, however, and entered Gascony, emanating a diploma at Castillon-sur-Dordogne the next year.