When someone does something that so viciously lacks in humanity, we call them a monster. Through action or belief, they have removed themselves from human decency, and become something grotesque. But society can also turn people into monsters through the way they’re depicted and treated. The portrayal of immigration as some insidious invasion — such as Trump’s 2015 comment on “people that have lots of problems” and “rapists” crossing the Mexico-US border — and the recent visual of children in cages at the border, simultaneously show how the both the marginalized and the powerful have been framed or frame themselves as monstrous.

Which is why the current exhibition at New York’s Morgan Library & Museum, while it features centuries-old manuscripts, feels timely. Medieval Monsters: Terrors, Aliens, Wonders is not just an exhibition of strange bestiaries and unicorns (although there are plenty of those); it is a thorough examination of how monsters were employed as propaganda in the Middle Ages. After it closes at the Morgan, Medieval Monsters will travel to the Cleveland Museum of Art (opening July 14, 2019) and the Blanton Museum of Art in Austin (opening October 27, 2019). The one-room show with around 70 manuscripts, sculptures, and other objects is mostly drawn from the Morgan’s collections, with some loans like a beautiful 1440 tapestry from the Museum of Fine Arts, Boston, with hairy “wild men” fighting Moors, both stereotyped as dangerous oddities.

“Monstrous imagery was often associated with members of socially disadvantaged groups in order to suggest that they were less than human; such a strategy rationalized repression and could even be used to instigate violence,” write curators Asa Simon Mittman and Sherry Lindquist in the accompanying catalogue. “In addition to the representation of nonnormative figures within European Christian culture, such as the mentally or physically impaired, whole groups of outsiders were also demonized. Representations of Jews and Muslims, whom Christians believed sinful for denying Christ, were made monstrous with exaggerated or animalistic features and graceless bodies, such as the caricatured representations of Jews — identifiable by their pointed hats — who torture Christ in a thirteenth-century German Book of Hours.”

In a 1227–37 French “Moralized Bible,” four roundels show Jewish people in pointed hats behind the Seven-Headed Beast and False Prophet from the Book of Revelation, and being pushed into hell, all affirming their status as outsiders and Christian persecutors. Meanwhile the 1420–25 French Hours of William Porter dramatically shows the torture of Saint Quentin by a man with a scimitar — an accessory to label him as Muslim — never mind that when the martyrdom occurred in the third century, Muhammad had yet to be born.

Other objects provide insight into the medieval perception of women, who could either be impossibly holy saints or treacherous femme fatales. One of the most striking illustrations is of a winged siren in the 1510 French Les abus du monde. She strides on bird’s feet triumphantly above a crowd of drowning men, wielding the harp and shawm (a woodwind instrument) on which she played her fatal song. The adjacent poem warns men about giving their faith to the charms of women, who lure with their looks while hiding their claws. Yet there were gender complexities that the medieval artists grappled with, including Mary Magdalene. It was only in the sixth century that she was transformed from a follower of Christ in the Gospels into a prostitute, her body then a battleground for sin and holiness, thus something supernatural. In a 1510 French Book of Hours, she ascends into heaven, born by angels, her nudity covered by a seductive flow of long hair. She is transgressive even as she achieves her saintliness.

Medieval Monsters also tackles how monstrous imagery could be a thing of power, either human or divine. On a 1500 English prayer roll, King VI is posed with an antelope, a symbol of otherworldly strength, as people during the period believed its menacing horns could cut down trees. And some of the more ghastly images in the exhibition are related to saints. Illuminators appear to have delighted in spattering the manuscript pages with crimson for the 1445–65 illustration of the martyrdom of Saint Denis, who stands upright, holding his severed head, defying mortality while blood spurts like a fountain from his neck. In a 1325–35 manuscript, Saint Bartholomew, flayed alive with his skin half-off to reveal a skeletal smile, appears ready to stand up from the torture table. Because of their closeness to God, these saints were superhumans escaping the natural order of the world.

You could fill a bestiary with the monsters at the Morgan, whether the hellmouth that visualizes the entrance to hell as a yawning maw, or the mandrake root that would shriek so loudly when harvested that foragers were advised to wear earplugs. There are even the invisible monsters within the body, which were frequently blamed for mental illness; a 1476–99 Austrian manuscript shows a black demon emerging from a possessed man during an exorcism, while in the background a monk thrusts his hand in a fire to resist the carnal lust prompted by a demon.

As the curators note, the word “monster” was linked by medieval scholars to the Latin monstrare — “to show” — and monere — “to warn.” Each of these artworks, even when created for amusement, was meant to show some perspective on the world, including a terror and curiosity for those people who lived in foreign lands. As our anxiety over the actions of other humans continues to be defined by words like “monster” and “monstrous,” which suggest something horrific and supernormal, Medieval Monsters offers a historical view of our tendency to morph those who are different into beasts.

Medieval Monsters: Terrors, Aliens, Wonders continues through September 23 at the Morgan Library & Museum (225 Madison Avenue, Midtown East, Manhattan).