Balsamo the Magician or the Memoirs of a Physician

Features one of the strangest characters in literature, Joseph Balsamo, also known as Cagliostro (later a key figure in the Affair of the Necklace). An alchemist, conspirator, and Freemason, Balsamo figures prominently in the eventual downfall of the French monarchy. (Excerpt from Goodreads)