Lovecraft was one of the first weird fiction critics to single out The King In Yellow for (qualified) praise in his treatise, "Supernatural Horror in Literature." Many other critics have since lauded its fever-dream atmosphere, filled with madness and nameless dread. We also know that A. Merritt was a fan of Chambers.

In popular culture, The King In Yellow formed the foundation for the first season of True Detective, which sparked a sharp upsurge of interest regarding Chambers' book. Long before that, however, there had been various anthologies written by diverse hands devoted to exploring RWC's Carcosa and the King In Yellow. By my rough count, there have nearly ten such in the last two decades or so, most in the last ten years. Obviously, there are those out there still intent upon finding the Yellow Sign.

So what has Chambers to do with sword and sorcery? The quotes above from Robert E. Howard and Karl Edward Wagner—read the full interview here—are evidence enough, in my opinion. In addition, Clark Ashton Smith ranked "The Yellow Sign" from The King In Yellow amongst his favorite weird tales of all time.

In the case of Robert E. Howard, the influence of Chambers runs deeper than just The King In Yellow. In fact, it's possible that particular volume was read much later by REH than several other tales from Chambers. A look at Howard's bookshelf shows he owned numerous novels written by RWC and none of them were The King In Yellow. No, all of the works owned by REH were from Chambers' later period, when he was one of the bestselling authors in the US.

The novels in Chambers' "Cardigan" series such as The Little Red Foot and America—books owned by Howard—are set during the American Revolution. Howard scholar, Rusty Burke, collated the texts of the three Cardigan novels owned by REH. He concluded that they were the source of nearly all the place-names found in Howard's Hyborian Age tale, "Wolves Beyond the Border." The political situation in the tale also echoes that found in the Cardigan novels. Some of the place-names used in WBtB were then carried over to the classic Conan yarn, "Beyond the Black River." Basically, Chambers provided inspiration and a partial template for Howard's "Pictish frontier" tales. Personally, I think that Howard also might have read RWC's The Hidden Children, which is part of the Cardigan series and shares a northern New York setting with the other novels. The Seneca shaman, Amochol, bears some resemblance to REH's Zogar Sag, in my opinion. The Hidden Children was published earlier than the three Cardigan novels we know Howard read. It was also made into a silent movie in 1917. I don't think it unlikely that Howard read the book.