Incubus

The weight comes first. A sleeper wakes in the black hours unable to move, the chest pinned as though a grown man were kneeling on it, the air squeezed thin in the lungs. There is a shape in the room, or the certainty of one, close and heavy and interested. The mouth will not open to scream. By morning the bedding is disturbed and the body wrung out, and across medieval Europe there was a name waiting for what had happened. Something had come in the night and lain upon her. The Latin said as much and no more: incubare, to lie upon, to weigh down, to brood. From that verb came the incubus.

The word is older than the demon it finally named. It surfaces in late antiquity, and Saint Augustine, writing The City of God, passed along as common knowledge that sylvans and fauns, commonly called incubi, had often forced themselves on women. He was not inventing the belief but reporting one people already held. Isidore of Seville drew the knot tighter a century or so later, noting that the creatures the Greeks called Pans and satyrs were the ones Latin speakers called incubi. So the demon that would trouble Christian Europe was stitched together out of the goat-legged woodland spirits of the pagan world, the fauns and satyrs who once chased nymphs through the trees, reissued now as agents of hell.

What it did was specific. The incubus came to sleeping women and pressed itself upon them, and its arrival felt like suffocation, a body settling onto the chest with all its weight behind it. The stories were describing something real, though not the thing they believed. The crushing pressure, the frozen limbs, the sense of a malign presence in a dark room are the exact signature of sleep paralysis, the half-waking state in which the mind surfaces before the body is released from its nightly stillness. People felt the weight and reached for the only explanation on offer. A demon had been there.

There was no single face to it. It could arrive as the formless shadow, or it could wear the shape of a courteous young man, which is how its most famous story tells it, and in its older skin it kept the marks of the satyr, horned and goat-shanked and rank. The form it chose depended on what it wanted.

The real trouble began when women turned up pregnant with no earthly father to name. The Church had built the incubus partly to answer exactly this, and union with one was said to bring forth witches, monsters, and deformed offspring. But the theologians had cornered themselves, because demons were spirits and spirits have no seed. Thomas Aquinas worked at the problem in the thirteenth century and arrived at a queasy fix. A single demon, he reasoned, could take a woman’s form and lie beneath a man as a succubus, gather his seed, then take a man’s form and lie upon a woman as an incubus, delivering what it had stolen. The demon fathered nothing of its own. It was a courier. Two centuries on, the Malleus Maleficarum, the witch-hunters’ manual, set out the same mechanism in cold procedural detail: devils collect human semen and inject it into other bodies. The child born of such a transfer even had a name, the cambion, half-human and marked by the manner of its making.

The most celebrated of those children was Merlin. Around 1136 Geoffrey of Monmouth wrote the story into his history of Britain’s kings. Merlin’s mother was a nun who swore she had known no man; what she remembered was a beautiful young stranger who came to her in secret, who held and kissed her and left her carrying a child. The visitor was an incubus, and the boy it fathered grew into the greatest wizard in the island’s legend, his gift of prophecy traced by the storytellers straight back to his demon blood. The incubus, then, did not only ruin women. Now and then it produced a prophet.

Europe held no monopoly on the belief, because the experience under it is universal. The Germans had the Alp, a night-thing that wore a cape to change its shape and sat on sleepers’ chests. Across the Germanic and Slavic lands the mare rode her victims down into airless dreams, her name surviving in the English nightmare and in the marelocks she was said to knot into their hair. Zanzibar has the Popobawa, Chile the Trauco, each a shape that comes in the dark to force itself on sleepers, each blamed for pregnancies no one could otherwise account for. The names change. The weight on the chest does not.

Its powers followed from its nature. The incubus could shift its shape, slip unseen through a locked door, hold a sleeper’s body frozen and helpless, and return to the same woman night after night until she wasted away. It carried the bottomless lust the Church assigned to fallen angels. Yet it could be kept out. The standing defenses against evil spirits worked on it: prayer, the crucifix, the relics of saints, the rites of exorcism. Folk practice added more. Saint John’s wort, cut at midsummer, was hung over doors and worn on the body because a demon was said to be unable to abide it in the room. Iron did its usual duty, a horseshoe or a blade laid beneath the pillow. And the plainest guard of all was daylight and company, for the incubus was a creature of the solitary dark and rarely troubled a sleeper who was not alone. It fed on isolation, and on the lack of it, it starved.

Frequently Asked Questions

What is an incubus?

An incubus is a male demon of medieval Christian and European folklore that lies upon sleeping women to have intercourse with them. It was blamed for erotic nightmares, the crushing sensation of sleep paralysis, and pregnancies with no known father, and its name comes from the Latin incubare, meaning “to lie upon.”

What is the difference between an incubus and a succubus?

An incubus is the male demon that preys on sleeping women, while a succubus is its female counterpart that preys on sleeping men. Medieval theologians held that a single demon could act as both, taking a female form as a succubus to collect a man’s seed and then a male form as an incubus to deliver it to a woman.

Was Merlin really the son of an incubus?

In legend, yes. According to Geoffrey of Monmouth’s account written around 1136, the wizard Merlin was conceived when an incubus in the shape of a handsome young man visited his mother, a nun who had known no mortal man. Storytellers traced Merlin’s prophetic powers directly to this demonic parentage.

What causes the feeling of an incubus attack?

The classic incubus experience, waking unable to move with a crushing weight on the chest and a sense of an evil presence, matches sleep paralysis. This occurs when the mind wakes before the body is released from the muscle stillness of sleep, and medieval people interpreted the pressure and helplessness as a demon lying upon them.

How do you protect against an incubus?

Traditional defenses against an incubus were the standard wards against evil spirits: prayer, the crucifix, saints’ relics, and exorcism. Folk remedies added Saint John’s wort hung at doors or worn on the body, iron such as a horseshoe placed under the pillow, and simply not sleeping alone, since the incubus was thought to prey on the solitary.

Related Entries

Succubus, Lilith, Cambion, Merlin, Satyr, Pan, Faun, Mora, Pesanta, Night Hag, Alp, Popobawa, Trauco, Baku, Djinn