Harry Young, a bartender at the #10 Saloon in Deadwood, was present when Wild Bill Hickok was killed. In a 1915 book, Young claimed that Hickok lost his last hand to William Massie, Kings full to four 7s. So what is the source of the Dead Man’s Hand of Aces and Eights?
Hickok expert Joe Rosa doesn’t buy the Aces and Eights story either—nor any other claim about the cards Hickok held when he was shot. When Hickok slumped over, the cards scattered all over the place.
As to where the story originated, it appeared as early as 1926 in Frank Wilstach’s Wild Bill Hickok: Prince of Pistoleers. It’s not clear where he got it.