Rodrigo Díaz de Vivar (1043 – 1099
El Cid was brought up at the court of King Ferdinand the Great and served Ferdinand's son, Sancho II of León and Castile. He rose to become the commander and royal standard-bearer of Castile when Sancho became king in 1065.
Sancho wanted to reunite all the three parts of his dead father's kingdom. Rodrigo lead the Castilian military campaigns against Sancho's brothers, Alfonso VI of León and García II of Galicia, as well as in the Muslim kingdoms in
After his brother's death, Alfonso returned from exile attempting to claim his dead brothers throne. El Cid then swore Alfonso to the throne and named him King.
Although, Alfonso feared that El Cid would not prove loyal, but with no proof. In 1074, El Cid married Alfonso's niece, Jimena. Some believe the marriage was encouraged by Alfonso to bring El Cid under his watchful eye. Alfonso never gave El Cid a chance to make a better name for himself in the military, and kept him from becoming famous.
El Cid soon became fed up, and in 1081, without Alfonso's permission, he invaded the city of Toledo.
This made Alfonso very mad, and his advisors told him that El Cid had tried to betray him by attacking the city without his permission, false information. Alfonso then banished him from the city of Castile.