The blade is named after its earliest known owner, Henri Delacroix, 5th Duc du Richat. Records seized in 1789 and now part of the Archives Nationales indicate that the Duc purchased the blade at auction for 12 écu d’argent. The auction, which dispersed the worldly goods of a metalworker who had vanished and was presumed to be dead, furnished a number of other impressive antiquities at surprisingly reasonable prices.
The Duc was taken enough with the dagger that he wore it on his person, ostensibly for self-defense. Its prominence in the Duc’s 1787 portrait in the Louvre indicates that he enjoyed flouting it, though the painting does notably show a much different handle than the later extant photographs. When the Duc disappeared in 1788, failing to appear in his chambers and presumed to have drowned during a late-night walk, the dagger passed into his estate’s general collection.
After being looted the following year, the dagger did not reappear in the official record until 1863, when it was listed in a catalog of antiquities for sale by Hans Colbert, a dealer in Aachen. His catalog photograph of the Richat Dagger is the only know represenation from life, as both Colbert and his house photographer, Jean-Baptiste Girodoux, vanished before the dagger could be sold.