This book is a biography of the Castilian knight Rodrigo Diaz de Vivar (c. 1043-99), better known as 'El Cid'. Born near the city of Burgos, El Cid served under various Castilian kings during the 'Reconquista' of the Iberian Peninsula. He was an accomplished solider and military commander and led several campaigns against Almoravid territories in al-Andalus. He also briefly served under the Muslim ruler of Zaragoza, Yusuf al Mu’taman ibn Hud and his son al-Musta’in II before returning to Castile in 1087. In 1090, El Cid led a combined Christian and Muslim army to lay siege to the important city of Valencia. He captured the city in 1094 and ruled it and the surrounding land as a semi-independent state until his death five years later during a siege by Almoravid forces, who had conquered much of al-Andalus the previous decade.

El Cid is a national hero of Spain and has featured in Spanish literature for centuries. This book recounting his life and achievements was published at Burgos in 1593.