Medieval sources represent leprosy (lepra in Latin, “lepre” in Middle English) as a grave illness, usually incurable except through divine intervention. Leprosy first manifested on a patient’s skin. As the disease progressed it would come to disfigure a sufferer’s face and limbs, finally resulting in death. Understandings of the causes of leprosy varied across different genres of writing and across different time-periods within the Middle Ages. Only after the advent of the Black Death in the mid-fourteenth century was the disease was thought to be “contagious” (in our modern sense of the word) (see Touati 1999).

“Leper” (leprosus in Latin) is the term used to designate someone suffering from leprosy. It is now considered a slur, but in the Middle Ages it was used without necessarily derogatory implications. In Old French or Middle English, a leper might also be known as a “lazer” — after the figure of Lazarus “covered in sores,” in Jesus’s parable of the rich man and the poor (Luke 16: 19-31). This etymology also explains why leprosaria, or hospitals for those suffering from leprosy, were also called “lazer-houses.” Another synonym for leper in Old French and Middle English is “mesel,” a term derived from the Latin misellus, or “miserable one.”

In recent years, leprosy has been renamed Hansen’s Disease, largely to protect patients from the stigma that the label “leper” carries. If treated, the disease can be cured. Nonetheless, it is estimated that at present two to three million people worldwide are permanently disabled by the effects of Hansen’s disease. While it is not clear how closely the medieval diagnosis of leprosy matches that of modern medicine, skeletons in the graveyards of leprosaria do show signs of the disease in its advanced stages. These findings suggest that modern and medieval diagnostic categories overlap, though probably not perfectly.

Related terms
Chronic disease
Corporal works of mercy


Historians of medicine have shown that for the most part, medieval physicians and surgeons treated leprosy as a disease of the body, not a disease of the soul. In other words, for medical practitioners, the disease had material causes and material effects. Fourteenth-century medical treatises, for instance, exhibit a “non-moralizing or ‘naturalist’ stance, in keeping with the Hippocratic tradition” (see Demaitre 1985).

However, religious and literary accounts were different. They tended to oscillate between two extremes of depicting leprosy. On the one hand, these texts might condemn lepers, interpreting their sickness as an indicator of sin or transgression. This tradition has biblical precedent in some of the stories of the “Old Testament,” for instance when Miriam is stricken with leprosy (Numbers 12), or King Uzziah is (2 Chronicle 26). On the other hand, religious and literary texts might exalt the disease – for instance, revealing that a leper was in fact an especially holy or even divine figure. In the Gospel of Matthew, when Jesus enumerates what were to become the corporal works of mercy (25:35-40), he concludes, “Amen I say to you, as long as you did it to one of these my least brethren, you did it to me.” In medieval stories, Jesus’s words sometimes find literal expression, as when a poor and sick leper is revealed to be Christ in disguise.

Here is a passage from fourteenth-century English homily, or sermon, in verse that exemplifies one of these two tendencies — the medieval habit of equating leprosy and sin. (The Middle English appears first, and the translation follows.)

For riht als leper mas bodi
Ugli, and lathe, and unherly,
Sua mas the filth of licheri,
The sawel ful lath, gastelye,
And the bolning of prive pride
Es leper, that na man mai hide.

[For just as leprosy makes the body
Ugly and loathsome and repulsive,
So the filth of lechery makes
The soul very loathsome spiritually,
And the swelling of secret pride
Is leprosy, which no man may hide.]

By contrast, here is a story from a fifteenth-century sermon on humility (itself a translation from Caesarius of Heisterbach’s story collection the Dialogus Miraculorum). It exemplifies the medieval tradition of elevating and revering the figure of the leper. It also shows medieval texts’ intense sensory attention to the leper’s disfigured body. (The Middle English appears first, and the translation follows.)

A bysshop in fraunce wesschyd leprys feet. The bysschop mette be the weye a lepre. The bysschop kyssed him. The lepre seyde: “Bysschop, for thi lownes [humility], wype wyth thi tunge oute of my nase the snevyl that hangyth ther-inne, for I may noht suffere no lynen cloth towche it, for it is so sore.’ The bysschop wyth his tunge lykkyd it out lowly [humbly]. And in his lykkyng, sodeynly out of the leprys nose fel a precyous ston in-to the byschopys mowth, schynyng bryht & swete smellynge. & forth-wyth, in the syht of the bysschop, the lepre stye up [ascended] to heven.

(There once lived a bishop in France who washed the feet of lepers. One day the bishop encountered a leper along the way. The bishop kissed him. The leper said, “Bishop, on account of your humility, wipe with your tongue out of my nose the snot that is hanging in there, because I cannot bear any linen cloth to touch it, it is so sore.” The bishop with his tongue licked it out humbly. And in his licking, suddenly out of the leper’s nose fell a precious stone into the bishop’s mouth, shining bright and sweet-smelling. And then, in the sight of the bishop, the leper ascended up to heaven.)

Evidence and Images

A fourteenth-century illumination from Avicenna’s medical Canon, picturing a leper with clapper and running sores

A fourteenth-century English illumination of the Emperor Constantine, his face disfigured by leprosy

Further Reading

Brenner, Elma. 2010. Recent Perspectives on Leprosy in Medieval Western Europe. History Compass 8(5): 388-406.

Demaitre, Luke. 1985. The Description and Diagnosis of Leprosy by Fourteenth-Century Physicians. Bulletin of the History of Medicine 59: 327-44.

Demaitre, Luke. 2007. Leprosy in Premodern Medicine: A Malady of the Whole Body. Baltimore: Johns Hopkins University Press.

Farmer, Sharon. 2005. The Leper in the Master Bedroom: Thinking Through a Thirteenth-Century Exemplum. In Framing the Family: Narrative and Representation in the Medieval and Early Modern Periods, ed. Rosalynn Voaden and Diane Wolfthal. Tempe: Arizona Center for Medieval and Renaissance Studies. 79-100.

Peyroux, Catherine. 2000. The Leper’s Kiss. In Monks & Nuns, Saints & Outcasts: Religion in Medieval Society, ed. Sharon Farmer and Barbara H. Rosenwein. Ithaca: Cornell UP.

Rawcliffe, Carole. 2006. Leprosy in Medieval England. Woodbridge: Boydell Press.

Touati, François-Olivier. 1999. Contagion and Leprosy: Myth, Ideas, and Evolution in Medieval Minds and Societies. In Contagion: Perspectives from Premodern Societies, ed. L. Conrad and D. Wujastyk. Aldershot: Ashgate. 161–83.

Julie Orlemanski, University of Chicago