We knew the phrase with certainty - it came from the "Well of Lost Souls". But on further reflection, we had no idea where that phrase, in turn, came from. It sounds Dantesque - but does it really have that kind of origin?
Jstor and Bartlett's came up empty. I trawled through all the limited numbers of websearch results - including Quake levels and a motley variety of poetry - but no mention was earlier than Indiana Jones and the Temple of Doom, wherein the Well of Lost Souls is a pit of snakes.
So... is that the earliest mention of the phrase? Does it have some other etymology? Enquiring Jasper Fforde readers want to know.