Gen. Ibn (pronounced Ben) Yusuf (Herbert Lom) of the Almoravid dynasty has summoned all the Emirs of Al-Andalus to North Africa. He chastises them for co-existing peacefully with their Christian neighbors, which goes against his dream of Islamic world domination. The emirs return to Spain with orders to resume hostilities with the Christians while Ibn Yusuf readies his army for a full-scale invasion.
Don Rodrigo Díaz de Vivar (Charlton Heston), on the way to his wedding with Doña Ximena (Sophia Loren), rescues a Spanish town from an invading Moorish army. Two of the Emirs, Al-Mu'tamin (Douglas Wilmer) of Zaragoza and Al-Kadir (Frank Thring) of Valencia, are captured. More interested in peace than in wreaking vengeance, Rodrigo escorts his prisoners to Vivar and releases them on condition that they never again attack lands belonging to King Ferdinand of Castile (Ralph Truman). The Emirs proclaim him "El Cid" (the Castillian Spanish pronunciation of the Arabic for Lord: "Al Sidi") and swear allegiance to him.