One day in the early 12th century, a priest named Norbert of Xanten was celebrating mass in a crypt, when something unexpected happened: a large spider fell from the ceiling and landed in the chalice containing the consecrated communion wine. The horrified priest saw the creature and (in the words of his biographer), “he was shocked, having life and death before his eyes”. But his pious fortitude overcame his natural repugnance, and so “he chose to undergo the danger and swallowed whatever was in the chalice”. When mass was over, believing he was going to die, he stayed before the altar, praying and commending his fate to God. Then his nose started to itch; he scratched it, and the spider was expelled by a sudden fit of sneezing.


For the anonymous author who recorded this incident, it was a story about the power of religious faith: Norbert’s faith in God allowed him to swallow the spider, and his faith was rewarded by divine intervention, which meant that the creature was safely expelled from his body.

Bizarrely, this is far from being a unique story, with numerous saintly priests said to have faced the same dilemma, and to have made the same choice. They, too, are saved, although the manner in which the spider is expelled varies: they erupt through itchy skin, crawl from pustules on various body parts, or reappear when the priest is bled. But they almost universally emerge not only alive but also intact, and are later killed and preserved as relics.

Such incidents were not confined to the realms of the miraculous, and the question of what to do if a spider (or another unpleasant creature, such as a fly) fell into the communion wine was seriously discussed by a number of clerical writers.

The question of what to do if a spider fell into the communion wine was seriously discussed by a number of clerical writers

Their concern was closely linked to the Catholic belief in transubstantiation, the doctrine which states that the communion bread and wine, once consecrated, turn into the actual body and blood of Christ. Once a spider had been immersed in this holy liquid, it could not simply be thrown away, but had to be treated with the respect due to the sacrament. Consequently, some authorities advised that the foreign body must be swallowed, however reluctant the priest was to do this. Others were more dubious about the wisdom of doing so: they worried that it was presumptuous to assume that God would intervene to save the priest’s life, and also (more prosaically) that he might be so repulsed that he would promptly vomit in church. For both reasons, it might be better to dispose carefully of the spider, either by pouring it into the sacrarium (the special sink reserved for the disposal of sacred liquids such as holy water) or by burning it and keeping the ashes with the church’s relic collection.

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A monk drinking
A miniature of a monk drinking. (Photo by: Christophel Fine Art/Universal Images Group via Getty Images)

A source of fear and disgust?

If stories such as Norbert’s illustrate the sometimes over-literal nature of medieval religious thought, they also suggest that fear of spiders is not a new phenomenon. Arachnids had some positive associations in the Middle Ages: their webs were used to treat minor ailments such as fevers and flesh-wounds, and some theologians (believing that all animals were created by God for the benefit of mankind) suggested that Christians should contemplate spiders “that apply themselves to their tasks” and learn from their persistence. Mostly, however, they were a source of fear and disgust. In particular, they were linked to sin and the devil: medieval literary texts are scattered with images in which their entrapment of flies is compared to the devil enmeshing the unwary in a web of sin, and dragging them off to Hell. In the context of such beliefs, spider-swallowing priests provided a powerful illustration of how the combined strength of God, the sacrament, and the holy man could overcome sin.

Medieval literary texts are scattered with images in which their entrapment of flies is compared to the devil enmeshing the unwary in a web of sin

Moreover, despite the fact that most European spiders are not poisonous, it was widely asserted by medical authorities that a person who swallowed a spider would die, or at least become seriously ill. Numerous stories circulated about people who killed themselves, or at least tried to, in this way. It was even claimed that the Black Death was caused by Jews who “wished to extinguish all of Christendom, through their poisons of frogs and spiders mixed into oil and cheese”. It was for this reason that the nuns of Chelas (Portugal), learning that their priest had swallowed “a great, black, horrible spider” along with the communion wine, insisted that he be bled at once. They hoped that this would remove the poison from his body, although in this case the spider “came out of his arm alive before any blood issued from the wound” – to the great amazement of the women, who responded both by giving thanks for the miracle and by showing off the spider to anyone who would look at it.

Although swallowing a spider was seen as a particularly frightening and dangerous experience, medieval people were also concerned about ingesting a range of other creatures.

Miracle collections include the stories of unfortunate individuals who had swallowed creatures including frogs, snakes and large worms, whilst medical texts include remedies for people who found themselves in similar predicaments.

Medieval people were also concerned about ingesting a range of other creatures…

One particularly colourful suggestion included hanging a man upside-down next to a plate of roast veal, in order to lure a snake out of his body; his family should hide behind the furniture, brooms in hand, ready to pounce when the creature slithered out. Such desperate remedies, however, were unavailable to priests confronted by spiders, who faced a choice between discreet, respectful disposal or swallowing, risking death, and hoping for a miracle.


Dr Katherine Harvey is a historian of medieval Europe based at Birkbeck, University of London. Listen to Katherine discussing whether the Medieval era deserves its reputation for poor hygiene and bad odours on the HistoryExtra podcast