He was born at Vivar near Burgos and brought up at the court of King Ferdinand I of Castile. After distinguishing himself in the king's military campaigns, he was appointed standard-bearer by the 
next King Sancho. After Sancho fell at the battle of Zamora in 1072, he remained at the court of Sancho's brother and heir, Alfonso, and in 1074 married a relative of the king, Ximena. 
In 1079 El Cid was with the army of Mutamid of Seville to defeat the invading Abdullah of Granada. Amongst Abdullah's followers was Count Garcia Ordono who was captured by El Cid. Garcia Ordono, however, was a favourite of King Alfonso who, already distrusting El Cid, ordered him into exile. He went into service of the Moorish kingdom of Saragossa where he learned Islamic politics, law and customs. 
In 1083 Alfonso tried a reconciliation which lasted only a short period; but when the Almoravides attacked Castile in 1087, El Cid returned to favour. This, too, did not last for very long as in 1089 
he was again banished. In the same year he began the conquest of Valencia, but it took until June 1094 before the city capitulated. He died there on 10 July 1099.
 

Source: Leo van de Pas