At least two things brought Peter Weiss' 'Marat/Sade' to mind

A speech by Cummings' character, pretending to be in sympathy with Robespierre, to the effect that the guillotine is too swift and efficient and how better it had been in the glorious days of prolonged, gory executions. Sade says very much the same in the play--whose full title, if you don't know it, is "The Persecution and Assassination of Jean-Paul Marat as Performed by the Inmates of the Asylum of Charenton Under the Direction of the Marquis de Sade."

Two, the heralding of the rise of Napoleon out of the chaos of Le Terreur.

Enough so that I wouldn't be surprised if the Austrian Weiss studied this old American film. Just like I suspect Arthur Kopit, while crafting his play "Indians," borrowed his basic conclusions about Buffalo Bill's "playing himself" from the 1944 William Wellman biopic "Buffalo Bill."

Post-war audiences may have thought that old movies missed or omitted such themes, but I am sure some post-war playwrights paid closer attention to them.