Orson Welles
Justinian

Laurence Harvey
Cethegus

Sylva Koscina
Theodora

Harriet Andersson
Mathawsintha

Michael Dunn
Narses

Ingrid Boulting
Julia (as Ingrid Brett)

Dieter Eppler
Thorsmund

Lang Jeffries
Belisar

Robert Hoffmann
Totila

Ewa Strömberg
Rauthgundis

Mircea Anghelescu
Aligern

Ion Dichiseanu
Furius

Adela Mărculescu
Aspa

Adrian Mihai

Emanoil Petruţ
Teja

Florin Piersic
Witichis

Friedrich von Ledebur
Hildebrand

Fory Etterle

Joachim Nottke
Narrator (uncredited)