The publication of Robert E. Howard's Solomon Kane story "Red Shadows" in the August 1928 issue of Weird Tales gave birth, unbeknownst to Howard, of the sword and sorcery genre. Between that year and 1934, Weird Tales (hereafter, WT) would publish more Solomon Kane stories and a smattering of his Kull stories, all of which landed squarely in the then un-titled genre. Of course it was the publication of "The Phoenix on the Sword", the first published Conan story in the December 1932 issue of WT that would cement him in history as the father of sword and sorcery. It was foreseeable that others would come along and attempt stories in the same vein as Howard's creations. While some of the stories of Clark Ashton Smith came close, the first person to take a serious stab at doing so was C.L. Moore with "Black God's Kiss" in the October 1934 issue of WT.
For a bit of autobiographical information on Catherine Lucille Moore, here is a quote from her short, yet entertaining "An Autobiographical Sketch of C.L. Moore":
"They found me under a cabbage plant in Indianapolis on the 24th of January, 1911, and I was reared on a diet of Greek mythology, Oz books and Edgar Rice Burroughs, so you can see I never had a chance".
To that can be added that she left college during the depression and worked as a secretary at the Fletcher Trust Company in her home town. She was driven by the stories she grew up loving along with a fascination with the pulp stories of her time and turned that passion to writing. Her first professional sale was a Northwest Smith story, "Shambleau" in the November 1933 issue of WT (if you're not familiar, Northwest Smith is a character created by Moore. He was a rogue starship pilot that some consider an early progenitor of Han Solo of Star Wars fame -- I personally don't adhere to this theory, but it is a theory). Just short of a year later, she would unleash Jirel of Joiry.
"[Jirel] was tall as most men, and as savage as the wildest of them....The face above her mail might not have been fair in a woman's head-dress, but in the steel setting of her armor it had a biting, sword-edge beauty as keen as the flash of blades. The red hair was short upon her high, defiant head, and the yellow blaze of her eyes held fury as a crucible holds fire" ("Black God's Kiss).
From Moore's description of her, it is not too hard to see why Lin Carter, in his book Imaginary Worlds, called her a "gal Conan" with her savage fierceness and sword-edge beauty, this is understandable. While this is not exactly an accurate character description on Carter's part, Jirel was the first female sword and sorcery protagonist. I have a theory, but I have found no backing for this anywhere in print, that Howard's character Red Sonya of Rogatino from the historical adventure "The Shadow of the Vulture" (January 1934, The Magic Carpet Magazine) was an influence on Moore's Jirel of Joiry, perhaps more so than Howard's Conan stories--and I should point out that while Red Sonya did precede Jirel, "Vulture" was not a sword and sorcery yarn; thus, Jirel's place as the first woman warrior of sword and sorcery is firm, and it makes her the first character to be based on Howard's Red Sonya--ahead of Roy Thomas and Barry Windsor-Smith's creation of Red Sonja for Marvel Comics. Of course, I assume a lot in believing myself correct.
It is interesting to point out that while Howard influenced Moore to create Jirel, she in turn might have influenced him to create Dark Agnès. Again this is theory not a proven fact, but it is known that he sent the manuscript for "Sword Woman" to Moore and that she enjoyed it and said she hoped that he found a publisher. The two characters are physically similar, but again, aside from an abandoned fragment written by Howard, his intentions for his Agnès de la Fère stories were that they be historical fiction, not weird fiction. As Howard Andrew Jones states: "[perhaps] he sent the stories her way because he sensed a kindred spirit, or because he wanted her to see he'd done something a little similar but hadn't been stealing from her. Perhaps he contacted her for a bit of both reasons" ("Howard's Journey: Historical Influences to Historical Triumphs"; Sword Woman and other Historical Adventures, Robert E. Howard).
In any case, I don't think either writer would have taken issue with one or the other "borrowing" his/her ideas; after all, they were both part of the Lovecraft Circle. In the circle, H.P. Lovecraft made it common practice to borrow ideas from one another and then seed said ideas into their stories bringing about a sense of verisimilitude. Consider the stories in which Howard mentions the Necronomicon or Lovecraft stories in which Howard's creations are mentioned. There was a sort of free wheeling and dealing of the pulps in their day.
Moore would publish a total of five Jirel of Joiry tales between 1934 and 1936; actually six, if the story "Quest of the Star-Stone" is counted. "Quest" was a collaboration with her husband Henry Kuttner (whose Elak of Atlantis stories will be looked at here in more depth soon) and was a perhaps one of the first cross-over stories ever written as it featured a team-up between Northwest Smith and Jirel. While the influence of Howard can be seen in the Jirel stories, both are people of action who take the fight straight to the source, to say that Jirel is a female Conan is misleading.
C.L. Moore wrote with an eye towards the supernatural. She, like Howard, was part of the Lovecraft Circle, and that influence is readily seen. Her stories build to something. There is a creeping of the plot, and by this I do not mean to infer that her plots drag, they do not; however, they do creep towards an often bitter resolution and suspense builds along the way. I defend my statement that her Jirel stories are sword and sorcery, but the action is often not in the sword swinging, the action is in the sense of suspense that Moore builds. I encourage you to seek out her Jirel stories and read them in sequence of publication (Paizo publishing has them for print in their Planet Stories line). Read together, they form a loose novel of sorts as each successive story often references events that took place before it.
A bit more biographical information is needed on Moore before I close this. Her marriage to Henry Kuttner ended when he died at a too young age in 1958. She would re-marry, but she disappeared from the science fiction community and stopped writing all together. In the early 70's she made a few appearances at conventions, but these were sparse. The sad truth was, she suffered from Alzheimer's disease and spent her final years in a coma. She died April 4, 1987.
Do yourself a favor. Read her stories. The Conan fan in you will enjoy "Black God's Kiss". It is a tale of a savage young woman, who wishes for revenge so greatly that she, literally, travels to Hell in search of it. You will enjoy it, and I believe you will read the other Jirel stories, and afterwards you may even seek out her Northwest Smith stories.
You will wish there were more.