Also released as Valley of the Swords, this lugubrious US/Spanish co-production features the usual mid-1960s "tax shelter" international cast. Broderick Crawford plays a despotic 10th century Spanish king who, in cahoots with the invading Moors, has banished handsome Castilian nobleman Spartaco Santoni. With the surreptitious aid of Crawford's daughter Teresa Velasquez, Santoni assembles an army to march against the Moors. In keeping with the 13th century epic poem from which this film was derived ("El Poema de Fernan Gonzales") Santoni's path is smoothed by the celestial intervention of patron saints Milan and Santiago. Among the big names picking up a few tax-free dollars in The Castilian are Cesar Romero, Linda Darnell, Alida Valli and Fernando Rey.
A Muslim ambassador exiled from his homeland, Ahmad ibn Fadlan finds himself in the company of Vikings. While the behavior of the Norsemen initially offends ibn Fadlan, the more cultured outsider grows to respect the tough, if uncouth, warriors. During their travels together, ibn Fadlan and the Vikings get word of an evil presence closing in, and they must fight the frightening and formidable force, which was previously thought to exist only in legend.