El Cid Campeador was the nickname of Rodrigo Díaz de Vivar, an 11th century Castilian nobleman and military leader who helped re-conquer Christian lands from Moorish rule in Spain. As a skilled warrior, El Cid helped various kings but was also exiled at times and offered his services to Moorish rulers. El Cid went on to capture the city of Valencia, ruling it as an independent kingdom until his death and establishing his legacy as a Spanish national hero.