A loud ranting voice. In the old mysteries all tyrants were made to speak in a rough ranting manner. Thus Bottom the Weaver, after a rant “to show his quality,” exclaims, “That's 'Ercles' vein, a tyrant's vein;” and Hamlet describes a ranting actor as “out-heroding Herod.”
In Pilate voys he gan to cry, And swor by armës, and by blood and bones.
Source: Dictionary of Phrase and Fable, E. Cobham Brewer, 1894