Rodrigo Díaz de Vivar, commonly known as El Cid, was a Spanish knight and military leader born around 1043 in Vivar, near Burgos. He became famous for his role in the Reconquista, the centuries-long effort to reclaim the Iberian Peninsula from Muslim rule. El Cid served both Christian and Muslim rulers during his lifetime, showcasing his skills as a warrior and diplomat. El Cid is best known for his exploits in battle and his legendary status in Spanish literature, particularly in the epic poem, Cantar de mio Cid. He died in 1099, and his legacy continues to be celebrated in Spain as a symbol of bravery and honor.