Niall MacGinnis
— Martin Luther
John Ruddock
— Vicar von Staupitz
Pierre Lefevre
— Spalatin
Guy Verney
— Melanchthon
Alastair Hunter
— Carlstadt
David Horne
— Duke Frederick
Fred Johnson
— Prior
Philip Leaver
— Pope Leo X
Heinz Piper
— Dr. Eck
Leonard White
— Emissary
Egon Strohm
— Cardinal Alexander
Annette Carell
— Katherine von Bora (as Annette Carrell)
Alexander Gauge
— Tetzel
Henry Oscar
Irving Pichel
— Brueck