The devious general Cethegus plays the Byzantine and Gothic forces against each other for his own gain.
| Actor | Role |
|---|---|
 Orson WellesJustinian | Justinian |
 Laurence HarveyCethegus | Cethegus |
 Sylva KoscinaTheodora | Theodora |
 Harriet AnderssonMathawsintha | Mathawsintha |
 Michael DunnNarses | Narses |
 Ingrid BoultingJulia (as Ingrid Brett) | Julia (as Ingrid Brett) |
 Dieter EpplerThorsmund | Thorsmund |
 Lang JeffriesBelisar | Belisar |
 Robert HoffmannTotila | Totila |
 Ewa StrömbergRauthgundis | Rauthgundis |
 Mircea AnghelescuAligern | Aligern |
 Ion DichiseanuFurius | Furius |
 Adela MărculescuAspa | Aspa |
| AAdrian MihaiNot listed | Not listed |
 Emanoil PetruţTeja | Teja |
 Florin PiersicWitichis | Witichis |
 Friedrich von LedeburHildebrand | Hildebrand |
 Fory EtterleNot listed | Not listed |
| JJoachim NottkeNarrator (uncredited) | Narrator (uncredited) |