Sancho III (Basque: Antso, Sanzio, Santio, Sanxo, Santzo, Santxo, or Sancio; French: Sanche; Gascon: Sans), called Mitarra (from the Arabic for "terror" or "the terrible"), Menditarra (meaning "the mountaineer" in Basque), was the Duke of Gascony in a very obscure period of its history between 864 and 893.
[1] He is shrouded in mystery and legend, but is regarded as a great fighter of the Reconquista[specify] elected to his post as Carolingian power waned by the native Gascons.
His genealogy is obscure, but he was probably a son of Sancho II Sánchez.
[2] During the reign of Sancho III, Gascony became de facto independent, owing no allegiance to the King of France.
He settled the Vikings at the mouth of the Adour and brought them under control[citation needed].