I had never heard of these ancient astronauts prior to today's review, and it appears that the story has only rarely appeared in English, primarily in a 1970s edition and the current Wesleyan one. Obviously, the Lovecraftian echoes in the description made me eager to find out more.
Fortunately for all of us, the Theosophists found the story a good fit for their weird theory that SF authors were channeling Theosophical truth subconsciously from a parallel universe, so in 1903 they produced a detailed précis of the novella, which I have posted here.
The anticipation of Lovecraft's many and varied monsters--Yog Sothoth and the Great Race come first to mind--is obvious. But the idea of a ring of beings godlike in their power anticipates, too, what we have learned about Gobekli Tepe, whose rings of standing stones were meant as stylized depictions of the gods. Surely ancient people really did stand amidst circles of "gods" (i.e., the stones) and imagine themselves communing with the world beyond worlds.
What is perhaps most amazing of all is that the novella displays infinitely more imagination than anything the ancient astronaut theorists have come up with.
* Just to make it more fun, after 1909 they started writing separately as J.-H. Rosny "aine" (senior) and "jeune" (junior).