Karloff's first major role came in a film serial, "The Hope Diamond Mystery" (1920). He was Indian in "Without Benefit of Clergy" (1921) and an Arab in "Cheated Hearts" (1921) and villainous in "The Cave Girl" (1921). He was a maharajah in "The Man from Downing Street" (1922), a Nabob in "The Infidel" (1922) and had roles in "The Altar Stairs" (1922), "Omar the Tentmaker" (1922) (as an Imam), "The Woman Conquers" (1922), "The Gentleman from America" (1923), "The Prisoner" (1923) and the serial "Riders of the Plains" (1923).