Sancho III of Navarre
The black eagle was originally the seal of King Sancho VII of Navarre but was later attributed to Sancho III of Navarre who, when incorporating Aragon and Castile, had under his crown all the territories of Basque culture and language, including those traditionally Castilian, since his kingdom reached from Galicia to Ribagorça. From a Basque nationalist interpretation, the rule of Sancho III constitutes a historical precedent for the aspirations of the unification of the Basque-speaking territories under one independent State. From a Spanish perspective, it is one of the first attempts at forming a unified Spain.