UNTIL fairly recently, it was rare to find Americans who were passionate about both medieval history and contemporary politics. Barring the odd Christian conservative, medievalists tended to lean left: a Marxist grad student, say, mucking around in land ownership patterns to show how past inequalities gave birth to present ones, or an environmentalist activist, perhaps, fascinated with vegetable-dyed handspun clothing. But when Americans invoked historical events in politics, they tended to be more recent—the founding of the republic; the struggle against slavery and segregation; victory over Nazi Germany.

This has changed. Since the September 11th attacks, the American far right has developed a fascination with the Middle Ages and the Renaissance—in particular, with the idea of the West as a united civilisation that was fending off a challenge from the East. The trend has been prodded along by the movement's discovery of its European counterparts, which have used medieval and crusader imagery since the 19th century. This is troubling to many of those who study the Middle Ages for a living.

The embrace of the medieval extends from the alt-right online forum culture that has exploded in the last few years to stodgier old-school racists. Helmeted crusaders cry out the Latin war-cry “Deus vult!” from memes circulated on Reddit and 4Chan. Images of Donald Trump, clad in mail with a cross embroidered on his chest, abound. Anti-Islam journals and websites name themselves after the Frankish king Charles Martel, who fought Muslim armies in the 8th century, or the (slightly post-medieval) Ottoman defeat at Vienna. Jihadists, meanwhile, use images of Muslim cavaliers from movies and videogames to illustrate their own war against a West they believe to be a reincarnated Byzantium. Indeed, much of the far right's attraction to the Middle Ages seems to be driven by a grudging admiration for Islamic State’s fusion of medieval motivation and modern technology.

For Americans who are indifferent to the Middle Ages, or think of it as an unpleasant plague-ridden prelude to the present, this might be of little consequence. But millions of others with mainstream or left-leaning beliefs are attracted to the medieval era—witness the popularity of Renaissance reenactments, or medieval-inspired fantasies like "Game of Thrones". In popularising the Middle Ages, are medievalists feeding a reactionary impulse? Followers of the alt-right would perhaps nod. Humans are natural conservatives who ought to take pride in their history, they might say; ethnic homogeneity is appealing. In an essay that purported to explain the alt-right for readers of Breitbart News, Milo Yiannapoulis, one of its editors, described a good portion of the movement as fuelled by the “conservative instinct,” including a preference for a preference for “homogeneity over diversity.”

Scholars who study the era have taken note. In a recent essay in the popular academic blog “In the Middle” Sierra Lomuto argued that medievalists had “an ethical responsibility to ensure that the knowledge we create and disseminate about the medieval past is not weaponised against people of colour and marginalised communities in our own contemporary world.” Academics are placing a new emphasis on the ways in which medieval societies differed from the homogeneous world imagined by the alt-right. Art historians document the appearances of dark-skinned migrants in northern Europe to show that medieval populations, if not quite as mobile as today, were still pretty mobile. Others focus on the multiethnic Kingdom of Sicily, where Norman kings employed Arab and Jewish administrators, or Christine de Pizan, who wrote treatises on military science in the 15th century, when the field was even more male-dominated than today. Progressives and reactionaries may both be drawn to the Middle Ages out of an affinity for “tradition,” says Shirin Khanmohamadi, a professor of literature at San Francisco State University who teaches a course called the Multicultural Middle Ages. But progressives would find it most interesting to explore "the premodern contribution to 'multiculturalism' and to other modes taken for granted as modern."

Academia's presentation of a nuanced view of the Middle Ages may reach more bookish white supremacists: Derek Black, son of the founder of the website Stormfront, has written about how he broke with his father's racial separatist vision while pursuing a graduate degree in medieval history. It is unlikely to reach those whose view of the era is mostly filtered through movies and videogames. But in pop culture as well, a deromanticised view of the medieval world exists, emphasising the grittiness, riotousness and bawdiness of the medieval city. “Game of Thrones” follows the adventurers of dwarves, eunuchs and other outsiders in lands plunged into ruin by a nobility intent on fighting a dynastic conflict based on the Wars of the Roses; its religious affairs are modelled not on the Crusades but on the internal turmoil in Christendom that preceded the Reformation. The more popular medieval history becomes, the more it may come to be seen not as an endorsement of homogeneity but a refutation, a world in which non-conformity was not debilitating deviance but a desire to strive for something better.