The Great God Pan
The Great God Pan is a horror and fantasy novella by Welsh writer Arthur Machen. Machen was inspired to write "The Great God Pan" by his experiences at the ruins of a pagan temple in Wales. What would become the first chapter of the novella was published in the magazine "The Whirlwind" in 1890. Machen later extended "The Great God Pan" and it was published as a book alongside another story, "The Inmost Light", in 1894. The novella begins with an experiment to allow a woman named Mary to see the supernatural world. This is followed by an account of a series of mysterious happenings and deaths over many years surrounding a woman named Helen Vaughan. At the end, the heroes confront Helen and force her to kill herself. She undergoes a series of supernatural transformations before dying and she is revealed to be the child of Mary and the god Pan.
The Dunwich Horror
Lovecraft's main literary sources for "The Dunwich Horror" are the stories of Welsh horror writer Arthur Machen, particularly "The Great God Pan" (which is mentioned in the text of "The Dunwich Horror") and "The Novel of the Black Seal". Both Machen stories concern individuals whose death throes reveal them to be only half-human in their parentage. According to Robert M. Price, "'The Dunwich Horror' is in every sense an homage to Machen and even a pastiche. There is little in Lovecraft's story that does not come directly out of Machen's fiction."