D'Argenson was a counter-revolutionary in 18th century France. On 23 July 1794, he and Rouvray encountered the First Doctor and his companions Susan Foreman, Ian Chesterton and Barbara Wright in a farmhouse twelve kilometres from Paris. Unknown to them, they had been followed by revolutionary soldiers.
D'Argenson began to lose his nerve, terrified of meeting the same fate as his family, who had been sent to the guillotine. D'Argenson panicked and exited the farmhouse and Rouvray followed him. Rouvray was shot and killed and D'Argenson tried to jump the fence, but the soldiers caught him and he was killed soon after. (TV: The Reign of Terror)