On a recent, grim Friday afternoon, I met Manuel Eisner, a compact, dapper professor of criminology at the University of Cambridge, in the lobby of his hotel in Oxford. Eisner, who is Swiss, was in town for the graduation of his daughter Nora, who recently completed a Ph.D. in astrophysics. For years, Eisner enrolled his wife and children to help count, catalogue, and visualize incidents of historical homicide. One study, of the deaths of more than fifteen hundred European monarchs between the years 600 and 1800, grew out of a family breakfast conversation. “This is kind of the habit. You develop a coding scheme,” Eisner said, as if he was confessing a weakness for cinnamon rolls. “And we ended up having this data set which nobody else had done before.”

In 2014, Eisner founded Cambridge’s Violence Research Centre, where he and a colleague, Stephanie Brown, a historical criminologist at the University of Warwick, have been mapping records of medieval murders in English cities. Last fall, they published a digital map of sixty-eight homicides in Oxford between 1296 and 1348. (Eisner’s wife, Ruth Schmid, who is a handbag designer, helped with the coding.) The map is a clickable scattering of dead shoemakers, Welshmen felled by arrows, and one case of a guy trying to join a choir, by force, after midnight, with a sword and being struck with a sparth, or battle-axe. “It’s a particularly complicated society in Oxford,” Eisner said, with some relish. Since the map went online, this was his first chance to walk the streets and inspect the locations for himself.

Eisner’s hotel was on George Street, a busy thoroughfare of tour buses, restaurant chains, and students, just outside the line of the old city walls, which had fallen into disrepair by the seventeenth and eighteenth centuries. The afternoon was bitter. Occasionally, the wind gave way to showers of cold, light rain. We turned right and passed the place where John de Luffenam was smote “in the breast with a knife even to the heart, whereof he died at once,” on a Thursday evening in November, 1344, after an argument involving a college cook.

Medieval Oxford had a murder rate about three times higher than London’s during the same period, and some sixty times the level Oxford has today. (At between sixty and seventy homicides per hundred thousand people, medieval Oxford’s rate compares, roughly, to that of present-day New Orleans.) The town was in decline as a center of the wool trade but alive with the mayhem of some fifteen hundred young men—loosely supervised, theoretically celibate, armed with crossbows—the scholars of the university. In the twelfth century, Oxford began to emerge, alongside Paris and Bologna, as one of Europe’s prime seats of learning. (All three had crime problems.) “If I wanted to give advice these days about, well, what could you do to really seriously increase levels of violence in our society?” Eisner said. “Probably I would say, ‘O.K., take a few thousand fourteen-year-olds, just males, out of their context, give them knives and lots of alcohol, and put them into halls—and wait and see.’ ” In the Oxford murders that Eisner has looked at, more than seventy per cent of the victims and the perpetrators were students. Ninety-nine per cent were male. (During the same period, eight per cent of London’s murderers were women.)

“I really like the view of this church,” Eisner said, as we turned onto Cornmarket Street and saw St. Michael at the North Gate, whose rough stone tower is about a thousand years old. “You can actually still see the medieval structure.” Eisner works from coroner’s rolls, pieces of old parchment, stitched together, on which clerks wrote descriptions in Latin of sudden deaths in the neighborhood. The accounts are, by turns, formulaic—giving the time (“between curfew and midnight”) and nearest feast day (“on Sunday, the feast of St. Edmund”)—and proto-forensic. A few yards farther down Cornmarket Street, in December, 1300, John de Ripon was discovered outside what is now a branch of Pret a Manger, with “a wound on the head resulting from a staff that was four inches long and two inches wide, and his head was beaten with a knife up to the brain.”

The coroner’s rolls are packed with medieval crime procedure. “It’s certainly not a lawless society,” Eisner said. Citizens were expected to raise the hue and cry when trouble broke out, or if they found a body on the road. (The “first finder” would then be vouched for by two other citizens and called to testify when a judge came to town.) Then the coroner, a royal official, would summon a jury of between a dozen and fifty men, from the four local parishes, to try to figure out what had happened. No one could touch the corpse until the jurors assembled. Eisner stood with his back to a café on Ship Street and pulled up the case of John Thresk, a Yorkshireman who was found dead in the churchyard of St. Michael’s on a Monday in November, 1343.

Thresk had been stabbed the night before with a knife worth two pence, by a fellow-northerner, John de Culvyntone. Both men were almost certainly students. But, when the coroner summoned a jury to investigate the killing, no one appeared. The same thing happened the following day. It wasn’t until Wednesday, when Thresk’s body had been lying in the churchyard for three days, that local men were willing to get involved. “What was it about this murder?” Eisner wondered. Oxford is the only city he has studied where juries occasionally refused to form. “They would have been punished for not showing up,” he said. “So why did they not do this?”

Eisner has a theory that relates to the way that medieval Oxford was governed. The university had considerable privileges. Beginning in the thirteenth century, it had its own chancellor, court, and system for regulating market prices, to make sure that students weren’t swindled by local tradespeople. As clerics, the students also fell under the protection of the Church, and this meant that they were almost never prosecuted under secular law for their crimes, including murder. “If you think about the impunity, it’s just extraordinary,” Eisner said. “You would not see that kind of thing happening in London.” It is possible that juries of townsmen were too scared, or simply unwilling, to get involved. “ ‘We can’t be bothered,’ ” Eisner speculated, of the mind-set. “ ‘This is not our law.’ ”

On occasion, friction between Oxford residents and students would escalate into full-scale riots, town versus gown. Eisner stopped on the corner of St. Mary’s Passage and the High Street, where, on a February afternoon in 1298, a crowd of scholars and manciples (men in charge of provisions for the university) armed themselves “with bows and arrows, swords and bucklers, slings and stones, and made an assault on all laymen that they could reach.”

In the rampage, a shopkeeper named Edward de Hales barricaded himself inside with his wife, Basilia. From an upstairs window, he shot a student named Fulk Neyrmit with an arrow through his left eye. Neyrmit died four days later. De Hales was arrested and held in the castle prison, from which he escaped on Christmas Day, before holing up in St. Michael at the North Gate. (In medieval England, fugitives could claim sanctuary in churches for up to forty days, while they negotiated with the local sheriff or made other plans.) In the end, de Hales agreed to abjure the realm, which meant walking, barefoot, to the port of Chester, a hundred and thirty miles away, holding a wooden cross and wearing sackcloth, and taking a ship across the Irish Sea, never to return. De Hales left Basilia, gave up his shop, and sold all of his possessions, including two feather beds, and some pots and utensils worth two shillings and sixpence. “They must have hated those kids,” I said to Eisner. “I’m sure they did,” he replied.

One of the great questions in criminology is why European societies have become less murderous through time. Between the fourteenth and the twenty-first centuries, the average homicide rate fell by about ninety-seven per cent. In 1939, Norbert Elias, a German sociologist and Jewish émigré to Britain, published “The Civilizing Process,” which argued that people’s personalities had been transformed, throughout the centuries, by the state’s increasing monopoly on violence and by complex webs of human interdependence—commerce, for example—that encouraged better manners and self-control. (Modern medicine has also played a role.) Eisner isn’t sure that our minds have changed all that much. Since 2004, he has helped to lead a longitudinal study of fourteen hundred young people, between the ages of seven and twenty-four, studying how aggression and violence manifest in childhood. According to Eisner, about twenty per cent of male teen-agers think about killing somebody in any given month.

“Fantasies of taking revenge, of killing somebody who’s insulted you, or killing somebody who’s been treating a good friend of yours badly, are quite pervasive,” he said. In its way, Oxford in the Middle Ages was a perfect laboratory of adolescent violence, with endless opportunities for slights and confrontation (town versus gown; rival halls; fights between “northern” and “southern” nations of students), awash with battle-axes, staffs, and vicious blades, and little chance of being punished. (In the spring of 1389, a band of northern students had a beef with the Welsh and roamed the streets shouting, “War, war, war, sle, sle, sle the Welshe dogges,” according to court papers.) “My working assumption is that what happened in the brains of medieval students who got into fights is basically what happens in our contemporary brains,” Eisner told me. “We are the same kind of humans.”

It’s only the context that has changed. Eisner turned off the High Street next to University College and opposite All Souls College—the heart of medieval Oxford, where students have messed around for eight hundred years—into an alley just wide enough for a bike or two. “This was called Gropecunt Lane,” he said. “It was the center of prostitution.” (The street is now called Magpie Lane.) Eisner led us back to the High Street, the broad, open road where almost a third of the recorded murders took place. “So much medieval violence is about reputation and respect and public space,” Eisner said. “They don’t fight somewhere in the dodgy side lanes. They want this to be seen.”

Soon, we reached a spot near the old East Gate of the city, where Philip Port, of Westwall, was chased by a group of five scholars, on a Sunday night in March, 1305. He had been invited to a tavern by John de Berdon, a manciple at one of the university halls. On his way home, Port was apparently ambushed. His head was cut open with an axe, “from one ear to another, so that all his brain was scattered outside,” and his right hand was cut off and laid next to his body. De Berdon fled and none of the attackers was ever identified.

Across the reach of centuries, Eisner was both impressed and mystified by the violence of the killing. “This is not the run-of-the-mill homicide,” he said. “They really destroy the body. This is as far as it can go in terms of taking revenge and disfiguring. Cutting the hand off—what is the symbolism behind that?” To Eisner, the murder recalled a modern-day drug execution in Mexico. “You have gang murders, where you actually try to symbolize. You inflict the punishment on the body so that everybody can see.” Again, there were oddities documented in the coroner’s roll. Port was killed under the city walls, near one of Oxford’s main gates, on a Sunday night. But his remains were not officially discovered until the following day. Lots of people must have looked the other way. Eisner was skeptical that the killers were unknown. “This is not a huge place,” he said. “This is fifteen hundred students.”

The jury that was convened was large, some thirty men—including William le Barber and Thomas le Loksmyth—and Eisner surmised that it must have made sense, in the most dangerous situations, not to inquire too forcefully. (In 1355, a dispute regarding the quality of wine served to a pair of students at an Oxford tavern escalated into the St. Scholastica Day riot, in which almost a hundred people were killed.) We turned back up the High Street, into the wind, past the closed gates of colleges, all of which were out of bounds to Oxford’s ordinary, unlearned medieval population. “None of the city authorities would have ever been permitted to go through these college gates. They are separate spaces, extralegal spaces,” Eisner said. He was a detective working the coldest file, with sympathy for all sides, feeling for the shape of everything he didn’t know. “Even if the jury had some suspicions about who these students might have been, they might have just said ‘We’ll never get anywhere with these stupid cases,’ ” Eisner said. Then he went back to his hotel. ♦