The Kingdom of León was a medieval kingdom in the northwest of the Iberian Peninsula, established in the 10th century. It emerged from the earlier Asturian Kingdom and played a crucial role in the Christian Reconquista against Muslim rule. León became a significant cultural and political center, known for its contributions to art, architecture, and law. At its height, the kingdom included parts of modern-day Spain and Portugal. The City of León served as its capital and was home to the famous León Cathedral. The kingdom eventually merged with the Kingdom of Castile in the 13th century, shaping the future of Spain.