Lewis Stone as Rudolf Rassendyll / King Rudolf

Alice Terry as Princess Flavia

Robert Edeson as Colonel Sapt

Stuart Holmes as Grand Duke 'Black' Michael

Ramon Novarro as Rupert of Hentzau

Barbara La Marr as Antoinette de Mauban

Malcolm McGregor as Capt. Fritz von Tarlenheim

Edward Connelly as Marshal von Strakencz

Lois Lee as Countess Helga

John George as Assassin

Snitz Edwards as Josef

Fairfax Burger as Bersonin

S.E. Jennings as De Gautet

Ted Billings as Train Passenger Eating Banana (uncredited)

Eric Mayne as Rudolf's Brother Lord Burlesdon (uncredited)

Lon Poff as Archbishop (uncredited)

Frederick Vogeding as Detchard (uncredited)