Anthony Quinn
Kiril Lakota
Laurence Olivier
Piotr Ilyich Kamenev
Oskar Werner
Fr. David Telemond
David Janssen
George Faber
Vittorio De Sica
Cardinal Rinaldi
Leo McKern
Cardinal Leone
John Gielgud
The Elder pope
Barbara Jefford
Dr. Ruth Faber
Rosemary Dexter
Chiara
Frank Finlay
Igor Bounin
Burt Kwouk
Chairman Peng
Arnoldo Foà
Gelasio (as Arnoldo Foa')
Paul Rogers
Augustinian
George Pravda
Gorshenin (credit only)
Clive Revill
Tovarich Vucovich
Niall MacGinnis
Capuchin Monk
Marne Maitland
Cardinal Rahamani
Isa Miranda
The Marchesa
Gerald Harper
Brian
Leopoldo Trieste
Dying Man's Friend
Peter Copley
English Cardinal
Arthur Howard
English Cardinal
Jean Rougeul
Dominican
Arnaldo Caivano
Dying Man (uncredited)