The famous remark on Napoleon’s 1804 execution of the Duke of Enghien gets pinned to Talleyrand, Fouché, and Napoleon himself, in roughly that order of confidence. Quote Investigator traces it to a magistrate few non-historians have heard of: Antoine Boulay de la Meurthe, in 1807. The Talleyrand attribution doesn’t appear until 1822, the Napoleon one until 1844.