Rodrigo Díaz de Vivar (c. 1043–1099), known as the medieval Spanish knight and warlord "El Cid," married Jimena (Ximena) Díaz (c.1046–1116) between July of 1074 and May of 1076. Jimena was the daughter of Count Diego Fernández de Oviedo and niece of Alfonso VI, king of Leon (1065–1070) and later king of a united Leon and Castile (1072–1109).
There are many stories and legends about El Cid, and a well-known Castilian epic poem written about him, El Cantar de mio Cid ("The Song of my Cid," known in English as The Poem of the Cid), that tells the story of El Cid during the Reconquista, or the "reconquest" of Spain from the Moors.
In one story, El Cid is killed in a siege, but his body is lashed to his horse and sent out to face the enemy. Thinking that El Cid has already been killed, the enemy were frightened into retreat by the resurrected El Cid, and even in death, El Cid led the Spanish troops to victory.
According to legend, Rodrigo was captivated by Jimena's beauty and fell in love with her at first sight. This might be true, but it's more likely that Rodrigo married Jimena in order to garner favor in the court of Jimena's uncle, Alfonso VI, and to establish his place in the Leon royal dynasty.
There's very little historical record about Jimena during the time of her marriage to Rodrigo. What is known is that from the time Rodrigo won the battle of El Cuarte in 1094 and regained control of Valencia, Jimena lived with Roderigo in Valencia until his death in 1099.
After Rodrigo's death, Jimena was his successor as ruler of Valencia until 1102, when Alfonso VI decided to abandon the city to the invading Almoravids and took Jimena with him to Castile.
A legend grew up around Jimena herself in Leyenda De Cardeña ("Legend of Cardeña") that Jimena lived in the abbey of the Monastery of San Pedro of Cardeña during her old age. What is more likely is that she lived in the nearby city of Burgos until her death, which occurred between 1113 and 1116.