Alfonso VI of León and Castile was a prominent king in the 11th century, ruling from 1065 to 1109. He is known for uniting the kingdoms of León and Castile, which significantly strengthened his power in the Iberian Peninsula. His reign was marked by military campaigns against the Moors and efforts to expand Christian territories. Alfonso VI was also a patron of culture and learning, promoting the use of the Spanish language and supporting the Santiago de Compostela pilgrimage. His leadership helped lay the groundwork for the later unification of Spain, influencing the political landscape of the region for centuries.