Afonso VIII was the King of Castile from 1158 until his death in 1214. He is known for his role in the Reconquista, the effort to reclaim the Iberian Peninsula from Muslim rule. Afonso VIII successfully led the Christian forces in the decisive Battle of Las Navas de Tolosa in 1212, which significantly weakened Muslim power in the region. His reign was marked by efforts to strengthen the kingdom and promote economic development. Afonso VIII also established important alliances through marriage, including his union with Eleanor of England, which helped solidify his position and influence in medieval Europe.