Afonso I of León, also known as Afonso VI, was a significant medieval king who ruled from 1065 to 1109. He was the first monarch to unite the kingdoms of León and Castile, expanding his territory and influence in the Iberian Peninsula. His reign marked a period of cultural and political development, as well as military campaigns against the Moors. Afonso I was known for his support of the Catholic Church and the promotion of the Reconquista, the effort to reclaim territory from Muslim rule. His leadership helped to strengthen the Christian kingdoms in the region, paving the way for future unification efforts in Spain.