One well-known legend about the Cid describes how he acquired his famous war-horse, the white stallion Babieca (Bavieca). According to this story, Rodrigo's godfather, Pedro El Grande, was a monk at a Carthusian monastery. Pedro's coming-of-age gift to El Cid was his pick of a horse from an Andalusian herd. El Cid picked a horse that his godfather thought was a weak, poor choice, causing the monk to exclaim "Babieca!" (stupid!) Hence, it became the name of El Cid's horse.

El Cid did not die as depicted in the film. He died peacefully in 1099 while ruling his principality on the coast of Spain. His wife Jimena continued to rule after his death.

After the death of El Cid, Babieca was never mounted again and died two years later at the incredible age of forty. His master had asked that his wife and famous steed be buried with him at the Monastery of San Pedro de Cardeña. But unfortunately their remains were removed after the Peninsular Wars and taken to the cathedral in Burgos where they were finally interred and where they currently rest today.

According to the legend of El Cid, in his youth Rodrigo came across a leper sinking in quicksand crying for help, but none of the bystanders dared touch him. Rodrigo pulled him from the bog, clothed him in his cloak, housed him in a barn and went to get him some food. When he returned, he found the leper had transformed into an angelic figure that identified himself as St. Lazarus. He said "For your bravery and kindness you will enjoy success as a warrior. You will win battles upon battles and never know defeat". In a nice nod to the legend, the film contains a scene wherein the banished Rodrigo encounters a thirsty leper who begs a drink. After unhesitatingly offering his own pouch, the Leper thanks him by name. "Who are you?" asks Rodrigo. "I am called Lazarus." The leper answers. Then he crosses Rodrigo with his staff. "May helping hands be extended to you everywhere you go, my Cid."

Perhaps somewhat surprisingly, Charlton Heston himself was not overly impressed by the finished film, suggesting in his 1995 autobiography "In the Arena" that the film might have been better if William Wyler had directed it instead of Anthony Mann.