Alfonso III was a king of the Kingdom of León, ruling from 866 to 910. He was known for his military campaigns against the Moors and for expanding his territory. His reign marked a significant period in the Reconquista, the effort to reclaim the Iberian Peninsula from Muslim rule. In addition to his military achievements, Alfonso III was also recognized for his administrative reforms. He established a more organized government and promoted the use of the Spanish language in official documents. His efforts helped lay the foundation for the future unification of Spain.