The fabled Spanish hero Rodrigo Diaz de Vivar (a.k.a. El Cid) overcomes a family vendetta and court intrigue to defend Christian Spain against the Moors.

Eleventh century Spain is divided into Christian kingdoms and Moorish strongholds. The young Rodrigo Diaz de Bivar (Charlton Heston), dubbed "El Cid" by his followers, vows to see his country at peace, free from the invaders. Vigorously brave and resourceful, the noble knight hates bloodshed and faces treason charges at court for the clemency shown to some emirs. His accuser, Gormaz (Andrew Cruickshank), father of his fiancée, Jimena (Sophia Loren), dies in the resulting duel. Jimena's avowed vengeance plot fails and Rodrigo is given her hand. The marriage is not consummated and she enters a convent. On Ferdinand's (Ralph Truman's) death, his kingdom is divided amongst his three children. Sancho (Gary Raymond) challenges the decision and imprisons Alfonso (John Fraser), who is released by El Cid. The African warlord, Ben Yussuf (Herbert Lom), takes advantage of the quarrel by having Sancho assassinated. Alfonso now claims that throne, too, and exiles El Cid. Jimena realizes the nobility of her husband and joins him, but returns to the convent with their two children, when he goes into battle against Ben Yussuf. The years pass, El Cid becomes a revered warrior, but refuses to aid Alfonso, preferring his own strategy. He lays siege to Valencia, catapulting food into its starving garrison. When the Valencians kill their evil ruler, Al Kadir (Frank Thring), they offer the crown to El Cid. He sends it to Alfonso, who rushes, hysterically gratified, to his side. But El Cid has been hit by a stray arrow. Attended by Jimena, he hides the wound from his men and prepares a final bid to drive the Moors from Spain.—alfiehitchie