Across the river from Heidelberg Castle, on the wooded summit the city calls its Holy Mountain, there is a hole in the ground behind an iron grate. It is two to three meters wide and drops 55 meters into bare red sandstone, straight down, roughly the height of a twenty-story building. The sources cannot even agree on that number: the standard archaeological survey says 55 meters; the local historical society and the museum’s 2020 camera expedition say 56. Nobody dug it yesterday; somebody cut every meter of it by hand.
The name is the oldest thing we can hold onto. Heidenloch: the heathens’ hole. In 1548 the cosmographer Sebastian Münster already wrote of “wondrously old holes, built by heathens” on this mountain, which means the name and the puzzle are at least five centuries old, and the hole itself is older than that. Since then it has been explained as a heathen work, a home of Satan, a passage to the river, an empty giant’s grave, a druid chamber, a Roman cistern, and a monastery well. The current explanation is the well, and it is a good one, though it hangs on a piece of masonry comparison, with an unresolved layer of possibly Roman brick sitting near the bottom.
What follows is the history of the answers: what each era needed the Heidenloch to be.
What the Spade Says
The hole has been emptied twice. Paul Herbert Stemmermann’s crew dug out the rubble fill between May 1936 and March 1938, first with ladders and winches, then with heavy equipment, for which they tore down the historic stone vault that had covered the mouth. Berndmark Heukemes cleared it again in 1987 for the state archaeology service, documented it properly, and had the most important stones lifted out and rebuilt in the Kurpfälzisches Museum down in the city.
Those stones are the core of the current reading. At the bottom of the shaft stood a well casing, 2.1 meters high, built from dressed blocks. Renate Ludwig and Peter Marzolff, in the standard survey of the mountain’s archaeology, date that casing to around 1100 by comparing its stonework with the east end of Speyer Cathedral, and conclude that Lombard masons from the Speyer workshops built it. The timing fits the neighborhood: the Stephanskloster, the smaller of the mountain’s two monasteries, was founded in 1094 a short walk away, and a community of monks on a dry sandstone summit needs water. In this reading the shaft is a heroic piece of eleventh- or twelfth-century labor that failed at its job. It never struck a water vein. It collected seepage, too little of it, and was given up and slowly swallowed by rubble.
The reading rests on real evidence and comes with loose ends, and the excavators recorded both. Ludwig and Marzolff note a second floor beneath the casing’s base plate, below 52 meters, made of brick courses they describe as possibly Roman. If those bricks are Roman, someone was cutting or using this shaft a thousand years before the monks, and the casing of 1100 becomes a renovation rather than a beginning. The find has not been resolved either way. There is also the odd distribution of the fill: the objects, the keys, horseshoes, stirrups, knives and worked stones from the monastery, all came out of the upper 26 meters. Below that, nothing but stone and gravel to the bottom. And at 22 meters down, scratched into the wall in thin lines, the diggers found the image of a woman. Nobody has explained her.
So even the sober version of the Heidenloch is a probability, not a verdict. Archaeology dates the casing, which dates only itself; the shaft has no date. For eight hundred years, people standing at this rim have been doing what the archaeologists do: reading the hole by what they brought up the mountain with them.
The Heathens in the Name
The medieval explanation is baked into the word Heidenloch itself. Whoever cut this shaft, the name says, was not us but the people from before, the heathens whose ruined walls already littered the summit when the name was given.
This was the standard medieval move. Confronted with a work too large or too pointless to attribute to any neighbor, you assigned it to the pre-Christian past, which functioned as an attic for the unexplainable. The mountain made the move easy, since a Celtic hilltop settlement stood here long before the monasteries and its double ring wall still circles the summit. The people who called the hole heathen were not wrong that older hands had shaped the mountain. They were guessing, but in a real direction.
The Heiligenberg carries at least three eras of construction stacked on one summit: a Celtic ringwall settlement, two medieval monasteries (St. Michael and St. Stephen), and a Nazi-era open-air amphitheater, the Thingstätte, built in 1934-35. The 55-meter shaft sits among them, older than some and younger than others, and the stories of all three eras have claimed it.
Around 1605 the preacher Rebmann gave the heathen attic a tenant: Satan himself had lived in the hole, dispensing false prophecies to the pagans, until Christian truth drove him out. The detail comes to us through the later literature rather than a text we have inspected ourselves, but it fits its moment. The Reformation era had inherited a landscape full of pre-Christian leftovers, and where the Middle Ages had been content to call them old, the confessional age preferred to call them damned.
The Man Who Laughed at the Goose
Around 1600 the geographer Matthias Quad wrote up Heidelberg for his survey of the German lands, and his chapter is the best early source we have, because Quad had stood on the mountain himself and looked into the holes. Holes, plural: he counts three “heathen” openings, two behind St. Michael’s church, filled with rubble, and one deep open shaft near the small All Saints chapel at the front of the mountain, which he had examined “in my time, namely around the year 1570.”
His description is precise in the way of a man leaning over an edge with his hat in his hand. A square, stone-framed mouth, about an ell and a half on each side. A few ells down, the opening widens and drops six or seven fathoms through bare rock, so smooth, he writes, that it is a wonder “whether it was formed thus by nature or by human work.” At the bottom, in the corner facing the villages of Neuenheim and Handschuhsheim, a door-sized opening bends slowly away toward the middle of the mountain, “so terrible and dark to look into that I can give no further account of its inward shape.”
Then Quad does something unexpected for 1609: he debunks.
The schoolboys of Heidelberg, he reports, liked to tell how a white goose was once thrown into the hole and came out at the Neckar river, dyed completely black. Quad has no patience for it: he calls the story “kinder klaff,” children’s prattle, and scolds the respectable authors who had printed it as fact. He is the legend’s first recorded debunker rather than its teller, and he complains, four hundred years before this article, that the print media of his day laundered playground rumor into geography.
What he offers instead, as “a more credible, or at least possible, legend,” is stranger and better. A Santiago pilgrim, “a good Jacob’s brother,” had twice climbed deep into the hole, to Quad’s knowledge, and reported a wide chamber below. On the side toward St. Michael’s church stood one great old chest, bound in iron. On the side toward Neuenheim stood two more. On each chest lay a large, black, shaggy dog, chained to it with a thick iron chain. And other such things, Quad adds dryly, “which everyone is free to believe.”
The dogs in the modern retellings, on the museum panels and in the local literature, have fiery eyes; Quad’s have none. They are just black, rough-coated dogs on chains, which is somehow worse. Somewhere in four centuries of repetition, a narrator felt the scene needed more and lit the eyes up. The embellishment has since become the “authentic” version, while Quad’s restraint, and his closing shrug that the reader may believe what the reader likes, has been forgotten.
One complication: Quad’s deep shaft sits by the All Saints chapel at the front of the mountain, while today’s Heidenloch lies by the Stephanskloster near the summit tower. The scholarship treats them as the same hole, and they may well be. But Quad never says so, and we could not find the identification cleanly established anywhere. Even the question “which hole are the stories about?” turns out to have some play in it.
The Goose Test
The goose story Quad laughed at was already old when he heard it. The Zimmern Chronicle, compiled in the mid-sixteenth century, tells it in one sentence: in the church on All Saints’ mountain there is a hole going deep into the earth, and a goose let down into it “came out again by the monastery at Neuburg,” a good two kilometers away on the river. No color change: the goose turns up elsewhere, which proves the hole goes somewhere.
A decade or so later, in the schoolboys’ version Quad recorded, the goose has learned drama: now she comes out at the Neckar itself, and black. Whatever is down there stains or scorches; the hole has acquired an atmosphere.
The same experiment, with the same bird, was being run on a limestone shaft in Derbyshire, England. At Eldon Hole, the pit locals called a gate to hell, travelers from at least the 1780s were told that a goose thrown in had come out at Peak Cavern, two miles away, stripped of her feathers. In the earliest recorded English version she is only bald. By the Victorian era she is scorched black by the fires below. Two holes in two countries, with no connection to each other, ran the identical folk experiment: send a goose down as a probe, and let her body, surfacing at the nearest famous cave or river, report the conditions below. In both places the report darkens over time, from featherless to fire-blackened, as the audience’s appetite grows.
Folklorists file the motif under “migratory legend.” When people cannot go down a hole themselves, they send a story down instead, and the story comes back changed. The goose is the story with wings on it.
The goose test failed geology in both countries. Eldon Hole and Peak Cavern belong to separate, unconnected cave systems, and the Heidenloch is a dead-end shaft in sandstone with no passage to the Neckar. A goose thrown into either would still be there.
The Poet and the Firewood Gatherer
On an October evening in 1840, Victor Hugo climbed the Holy Mountain in the moonlight. He was gathering material for what became Le Rhin, his great Rhine travel book, and Heidelberg had already given him ruins enough. Near the summit he found what he describes as a singular square pit, ten or twelve feet deep, with stone slabs at the bottom, massive old masonry, vague remains of sculpture, and a rounded block pierced by a small square opening that struck him as either a Celtic altar or a tenth-century capital.
He stood at the edge in the dark and wondered what the pit was. And then, in his own words: “At that moment I heard a grave, cracked voice behind me distinctly pronounce the word: Heidenloch.”
If Hugo’s account ended there, the museum panels would be right to file him among the hole’s ghost stories, but it does not. Hugo turned around and found the voice belonged to an old woman gathering firewood on the slope, who repeated the word for him, three times, with the patience of a local explaining the obvious to a tourist. He gave her some coins. The ghost story dissolves on the page, by the author’s own hand, into an anecdote about a poet startled in the dark by an ordinary human being.
Two things follow. First, the pit Hugo describes is three or four meters deep, not fifty-five; whether he ever stood at the shaft this article is about is not provable from his text, and on the numbers alone it seems doubtful. Second: the retellings that quote Hugo as the poet who heard a ghostly voice at the Heidenloch have done to him what four centuries did to Quad. They kept the shiver and cut the punchline. Hugo debunked his own ghost within a paragraph, and posterity un-debunked him. That makes two of the hole’s storytellers who tried to lower the temperature and were overruled after their deaths.
Well or Sacrifice Shaft
You might expect the arguing to have stopped by now, but it has only become better mannered.
The academic position, Ludwig and Marzolff’s, stands as described: a water shaft for the Stephanskloster, casing around 1100, a failed and abandoned well. The local historical society that cares for the mountain, the Schutzgemeinschaft Heiligenberg, disagrees on its own website: a well or cistern is unlikely for geological reasons, they argue, given the water veins in the hill and the nature of the sandstone, and a Celtic sacrificial shaft is the more plausible reading, since the Celts of the ringwall era had the manpower, though comparable Celtic shafts elsewhere reach only around 35 meters. They give no sources for the geology or the comparison, so we report the claim as what it is: the living local counter-position, unreferenced but seriously meant.
The disagreement is respectable rather than crankish, because archaeology itself has changed its mind about this kind of hole before. At Fellbach-Schmiden near Stuttgart, inside a Celtic square enclosure, excavators in the 1970s found a wood-lined shaft twenty meters deep containing three carved oak figures, goats and a stag from a cult frieze, with the lining timbers felled, the tree rings say, in the spring of 123 BC. For years it was read as a ritual shaft, an offering pit. The current reading is a well: there was a wooden bucket at the bottom, a ladder for maintenance access, and a proper lining, and the carvings are now understood as things that ended up in the water rather than reasons the shaft was dug. A hole can be sacred and still be plumbing, and a well can retire into a reliquary; the categories leak, and the same evidence can change teams a generation later.
Held against Fellbach’s checklist, the Heidenloch shows a casing, which argues for a well; no water, which sits badly with a competent one; and a possibly Roman floor that nobody has explained. In 2020 the state heritage office lowered a purpose-built camera rig all 56 meters to the bottom and produced a 3D model of the whole shaft. The film they released about the expedition is titled, in translation, “Enigmatic Heidenloch.” That is the current, instrument-verified position of the institutions responsible: enigmatic.
What Actually Came Out
Eight hundred years of stories went down the hole; here is the complete list of what has come up.
Keys, horseshoes, stirrups and knives from a working monastery; cut stones and column pieces from its buildings; pottery from around 1400 and pieces of a tiled stove. And, from the same late-medieval layer, weapons: a dagger, an armor-piercing blade, a war fork, which the museum’s account connects to some violent event at the Stephanskloster around the end of the fourteenth century, its traces cleared away and dumped where Heidelberg had always dumped what it wanted out of sight. Below 26 meters there was nothing but rubble, and no chests, chains, or dogs anywhere. The woman scratched into the wall at 22 meters keeps whatever she knows to herself.
Modern cavers who have been down report their own find, summed up in a local newspaper headline as heaps of trash and coins. The coins are easy to picture: visitors tossing them through the grate, the way people do at any dark opening that might be listening. Satan’s prophecy office, the goose tunnel, the treasure chamber with its chained dogs, and at the bottom of it all, small change thrown in on the same instinct that dug the legends. The Heidenloch has never once answered a question. It has only ever received them, 55 meters of them, or 56, depending on whom you ask.
Sources
Bibliography. The same list is held in the article’s frontmatter for the citation tools that read it programmatically.
- Matthias Quad (von Kinckelbach), Teutscher Nation Herligkeitt, Cölln am Rhein: Lutzenkirchen, 1609, Cap. 36, pp. 140-141 (digitized: Bayerische Staatsbibliothek, urn:nbn:de:bvb:12-bsb11072899-5)
- Zimmerische Chronik, vol. 3, p. 362 (ed. Barack; digitized at Wikisource)
- Victor Hugo, Le Rhin / En voyage, tome I, Lettre XXVIII ‘Heidelberg’, October 1840 (French text at Wikisource)
- Renate Ludwig and Peter Marzolff, Der Heiligenberg bei Heidelberg, 2nd ed., Stuttgart: Theiss, 2008, pp. 100-103
- Berndmark Heukemes, ‘Erneute Untersuchung des Heidenlochs auf dem Heiligenberg bei Heidelberg’, in: Archäologische Ausgrabungen in Baden-Württemberg 1987, Stuttgart: Theiss, 1988, pp. 193-196
- P. H. Stemmermann and C. Koch, ‘Der Heilige Berg bei Heidelberg’, Badische Fundberichte 16, 1940, pp. 42-94
- Kurpfälzisches Museum / Landesamt für Denkmalpflege Baden-Württemberg, ‘Rätselhaftes Heidenloch — Filmexpedition in die Tiefe’, camera survey of July 16, 2020
- Schutzgemeinschaft Heiligenberg / Handschuhsheimer Geschichtswerkstatt, ‘Geschichte des Berges’ (heiligenberg-handschuhsheim.de)
