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

Lee Kresel

King Louis XVI / Innkeeper

Robert Atkins

King Louis XV

Nicholas Bruce

De Remy

Franco Corsaro

Chico

Annielo Mele

Joseph Balsamo as a Child

Ronald Adam

Court President

Bruce Belfrage

Crown Prosecutor

Alexander Danaroff

Dr. Duval / Baron von Minden

Leonardo Scavino

Gaston / Beniamino Balsamo (as Leon Lenoir)

Tamara Shayne

Maria Balsamo

Joop van Hulzen

Minister of Justice

Peter Trent

Dr. Mesmer's Friend

Giuseppe Varni

Boehmer

Tatyana Pavlova

Grieving Mother

Harriet Medin

(uncredited)

Valentino Bruchi

(uncredited)

Ludmilla Dudarova

(uncredited)

Rosina Galli

(uncredited)

Silvana Mangano

(uncredited)

Filippo Minelli

(uncredited)

Michele Sakara

(uncredited)

Nicholas Soussanin

(uncredited)

Milly Vitale

(uncredited)