Bytting — the changeling left in the cradle
The non-human child the hidden folk leave in the cradle in place of a stolen human infant. Under the trolls is a colder story — it was the explanation a farm reached for when a baby was born disabled or would not thrive, and the cures it prescribed were real.
Between birth and baptism a child was unguarded, and in that gap the underjordiske could lift the human infant out of the cradle and lay one of their own in its place. What they left behind was a bytting.
A bytting did not thrive. It did not learn to walk. It ate everything brought to it and did not grow, and watched the room with a stare that fixed on nothing in it. There was a country test for it: you set seven eggshells on the hearth, filled them with water, and made a show of brewing beer in them. The thing in the cradle would sit up and speak then — an old man’s voice out of a baby’s throat — saying it had lived long enough to see the forest grow seven times over and never seen anyone brew in an eggshell.
Strip away the trolls and the bytting is the explanation a farm reached for when an infant was born disabled, would not thrive, or stopped growing — and the cures the lore prescribed were the abuse and killing of those children. The Asbjørnsen version, gathered into Norske Huldreeventyr og Folkesagn in 1848, has the bytting carried out to the pigpen and switched on three Thursday evenings running. The recorded prescriptions across Scandinavia were worse: the child held to a heated bakeoven, laid out on the dunghill, beaten, or put in water, on the belief that the hidden folk would take their own back and hand over the real child whole. Court records from Scandinavia, Britain, and Ireland into the nineteenth century show these were not only told but done — suspected changelings tortured and killed, and the killings prosecuted.
Against the theft, the cradle was armoured: a knife or open scissors laid crosswise over the child, a psalmbook under the straw, a light kept burning, and the infant baptized as fast as the parish could manage — because the underjordiske could only take a child who had not yet been christened. (The same fear of that gap ran into the law: a woman whose newborn died before baptism could be presumed a murderer under the 1687 statute, the one that also haunts the utburd.)
In the tale Asbjørnsen recorded, the switch comes down for the third time and the bytting is named Tjøstul Gautstigen. Somewhere inside the mountain the stolen child hears it and answers from inside the rock: Hver gang du slår ‘n Tjøstul Gautstigen, så slår de meg igjen i berget — every time you strike Tjøstul Gautstigen, they strike me again in the mountain.