Orson Welles

Joseph Balsamo aka Count Cagliostro

Nancy Guild

Marie Antoinette / Lorenza

Akim Tamiroff

Gitano

Frank Latimore

Gilbert de Rezel

Valentina Cortese

Zoraida

Margot Grahame

Mme. du Barry

Stephen Bekassy

Viscount de Montagne

Berry Kroeger

Alexandre Dumas, Sr.

Gregory Gaye

Chambord / Monk (as Gregory Gay)

Raymond Burr

Alexandre Dumas, Jr.

Charles Goldner

Dr. Franz Anton Mesmer

Robert Atkins

King Louis XV

Nicholas Bruce

De Remy

Franco Corsaro

Chico

Ronald Adam

Court President

Bruce Belfrage

Crown Prosecutor

Leonardo Scavino

Gaston / Beniamino Balsamo (as Leon Lenoir)

Tamara Shayne

Maria Balsamo

Joop van Hulzen

Minister of Justice

Peter Trent

Dr. Mesmer's Friend

Tatyana Pavlova

Grieving Mother

Harriet Medin

(uncredited)

Ludmilla Dudarova

(uncredited)

Rosina Galli

(uncredited)

Silvana Mangano

(uncredited)

Michele Sakara

(uncredited)

Nicholas Soussanin

(uncredited)

Milly Vitale

(uncredited)