The book by the famous Spanish philologist and historian Ramon Menendez Pidal is dedicated to the national hero of Spain - Rodrigo Diaz de Bivar, nicknamed Cid Campeador (11th century). Cid Campeador was a Spanish knight who actively participated in the Reconquista - the wars between Spanish Christians and Muslims for the right to live on the Iberian Peninsula. A man who knew the disfavor of kings, the anger and betrayal of his comrades, who fought alone for many years, Sid bore the brunt of the military conflict without betraying his principles, and went down in legend as the noblest and bravest of the Spaniards. The story of Campeador is the story of a man who became a symbol of the Spanish character, proud, noble and unbending. Talking about Sid, Menendez depicts the confrontation between two Spains - Christian and Muslim, who met in a mortal duel, from which only one side was destined to emerge. A brilliant expert on medieval Spanish literature. Menedes Pidal created a most interesting biography that has gone through a record number of publications in Spain and Western Europe.