At one point in the show Mrs. Mulvany quotes a line from Catullus, poem #73, and the complete version is Desine de quoquam quicquam bene velle mereri, aut aliquem fiere posse putare pium. For those listeners who are not fluent in Latin, we thought we would provide a translation: "Give up wanting to deserve thanks from anyone, or thinking that anybody can be grateful."

In the climactic scene of the story Delapore begins ranting in a combination of Gaelic, Latin, and Middle English. Lovecraft lifted the Gaelic from a story called "The Sin Eater" by Fiona Macleod, which was a pen-name of the Scottish writer and poet William Sharp (1855–1905). For those listeners who are not fluent in Gaelic, we thought we would provide a translation of the curse: "God against thee and in thy face—and may a death of woe be yours. Evil and sorrow to thee and thine!"

You can read "The Sin Eater" at the Internet Archive.

The Piltdown Man specimen was "discovered" by Charles Dawson, an amateur British archeologist who seems to have been something of a con man. When Lovecraft wrote the story in 1923, many people were familiar with Piltdown Man and most lay people believed it was genuine: Clarence Darrow even cited it as evidence during the Scopes Monkey Trial in 1925. In 1953 new evidence, including the fluorine absorption test, proved that the specimen was a forgery composed of a human skull of medieval age, the 500-year-old lower jaw of an orangutan, and chimpanzee fossil teeth, all of which had been stained and/or filed down to look old. The identity of the forger has never been definitively established, although the suspects include Dawson, Pierre Teilhard de Chardin, Martin A. C. Hinton, and Arthur Conan Doyle.

Lovecraft repeatedly refers to "coarse vegetables" during the story, a phrase which struck us as slightly strange. But it seems that "coarse" vegetables are legumes, such as beans and lentils, plus root vegetables, cabbage, cauliflower and onion. Coarse vegetables are often grown on open land, rather than in greenhouses, and can be stored for longer periods than more delicate "salad" vegetables such as tomatoes, lettuce and cucumber.

Some people believe that one of the inspirations for this story was the legend of Hatto II, archbishop of Mainz from 968 to 970. According to folktales, Hatto was cruel and oppressive, but justice was served when he was eaten alive by mice (or rats) in a tower on a small island in the Rhine near Bingen, Germany. There's a great old castle just across the river from the "Mouse Tower" called Ehrenfels Castle which might have inspired Exham Priory. Hatto was depicted, complete with rampaging rodents, in the Nuremburg Chronicle, and his story is told in Curious Myths of the Middle Ages by Sabine Baring-Gould.

As we were working on the script for this episode, we became aware of the real de la Poer family, headed by Henry Nicholas de la Poer Beresford (pictured below), the 9th Marquis of Waterford in Ireland. He recently inherited the title along with the alleged curse that comes with it, and a house not entirely unlike Exham Priory called Curraghmore House: "The house itself looks forbiddingly gothic. It’s actually a Norman keep encased in a Victorian mansion, surrounded by Georgian ranges, a landscaped garden and 3,000 acres of land. The de la Poer family has lived here for 800 years." We wish them the best of luck with the curse. There's no mention of rat hordes, but the real de la Poers do seem quite fond of playing polo.