IN 1939, at one of civilization's lowest points, a little-known Swiss sociologist, Norbert Elias, published a book called "Über den Prozess der Zivilisation" ("On the Civilizing Process") with a strange and unlikely thesis: that the gradual introduction of courtly manners — from eating with a knife and fork and using a handkerchief to not spitting or urinating in public — had played a major part in transforming a violent medieval society into a more peaceful modern one.

Hitler invaded Poland that year, and Elias's book was consigned to obscurity. It was not published in the United States until 1978 (with the title "The History of Manners"). But since then his seemingly eccentric thesis has been revived, and Elias has posthumously become the theoretical guru of a field that did not exist in 1939: the history of crime. It was then that pioneering historians began to do what most historians had thought impossible: create crime statistics for eras that did not systematically keep crime data.

"The Elias theory got revived through the statistical approach to history," said Elizabeth Cohen, a historian at York University in Toronto who has written extensively on crime in Renaissance Italy.

Although there were no national statistics centuries ago, some historians discovered that the archives of some English counties were intact back to the 13th century. So in the 1970's they began diligently counting indictments and comparing them with estimated population levels to get a rough idea of medieval and early modern crime rates. Historians in Continental Europe followed suit and came up with findings that yielded the same surprising result: that murder was much more common in the Middle Ages than it is now and that it dropped precipitately in the 17th, 18th and 19th centuries. Something very important changed in Western behavior and attitudes, and it stood much prevailing social theory on its head. "It was very surprising because social theory told us that the opposite was supposed to happen: that crime was supposed to go up as family and community bonds in rural society broke up and industrialization and urbanization took hold," said Eric H. Monkkonen, a professor of history at the University of California at Los Angeles and the author of several works on the history of criminality. "The notion that crime and cities go together made emotional sense, particularly in America, where at least recently crime is higher in cities."

Some scholars argue that many of the prevailing theories about why crime rises and falls could be further upended as scholars use new computer models to estimate population figures for past eras more accurately. "With modern computing we may end up with some very good estimates in the homicide rates in many nations right back to the 17th and 16th centuries," said Randall Roth, a historian at Ohio State University who has recalculated murder rates for the 15th and 16th centuries in many countries. "The data we are getting doesn't line up with most theories of either liberals or conservatives about crime. The theory that crime is determined by deterrence and law enforcement, by income inequality, by a high proportion of young men in a population, by the availability of weapons, by cities, most of those theories end up being wrong."

Historians have offered various explanations for the unexpected fall in the crime rate. Initially some wondered whether the decline in early modern crime might be a result of industrialization and urbanization themselves. But James A. Sharpe, a historian at the University of York in England, said the big statistical dip in violence preceded industrialization and urbanization by more than a century.

Other scholars then theorized that crime had not diminished but only shifted from bodily assault to crimes of property, reflecting the change from a world of medieval scarcity to one of greater prosperity and availability of material goods. But this theory, too, has not stood the test of time. "The great decline in homicide in the 17th century was not accompanied by a rise in property offense prosecutions, but rather by their diminution," Mr. Sharpe noted in a recent essay.

All these discredited theories helped change "the status of Elias from curiosity to prescient thinker," Eric A. Johnson (a professor at Central Michigan University) and Mr. Monkkonen wrote in the recent book "The Civilization of Crime." That the decrease in crime appears to have happened independently of industrialization or economic growth seemed to suggest that an internal, psychological shift had taken place in attitudes toward crime. Advertisement

So did its changing nature. Widespread evidence indicates that in the Middle Ages physical violence, even to the point of death, was a widely accepted way of resolving disputes and defending one's honor. Most killings occurred in public in front of many witnesses when a dispute, generally among neighbors, got out of hand.

"People don't yet treat it as a crime and the perpetrator is not a social outcast," said Dan Smail, a historian at Fordham University in New York who has studied crime in southern France in the 14th century." (Still, Mr. Smail said, Elias got it only half right, arguing that it was the greater resources available in the early modern period that made it possible for people to get even with their enemies through law suits and conspicuous consumption rather than with fists and knives.)

That murder was accepted is reflected in the leniency with which it was generally treated, said Barbara A. Hanawalt, a historian at Ohio State University whose work on 14th-century England helped stimulate the interest in the history of murder. "Only 12 percent of homicides actually end in conviction," she said. "That's lower than larceny, which was 23 percent, and crimes of stealth, burglary and counterfeit," for which the rate was about 100 percent.

But after the late Middle Ages, Ms. Hanawalt detects a marked shift. "There is a real change in community tolerance," she said. "The state is more prominent, the local community has less control."

"I think Elias is onto something: people begin to change their notions of how people should behave," Ms. Hanawalt continued. "In the 14th century people are concerned with whether someone is of good or ill repute; it's a collective, community judgment. When you get into the 15th century, the question is about someone's `governance.' There is a shift from community reputation to an emphasis on internal control." A proliferation of tracts and manuals on proper behavior trickle down to common, illiterate folks in the form of rhymes and ditties.

One recent scholarly book on the history of murder, "Mad Blood Stirring" by Edward Muir at Northwestern University, describes one way in which this process may have occurred. In the book Mr. Muir describes how the Republic of Venice tried to put an end to violent feuding among unruly nobles as it extended its influence into remote rural areas in the 17th century. The wars fought over generations by the area's leading families left the region vulnerable to foreign invasion. Venice reacted by first meting out stiff punishment, then by drawing the rural noble families into Venetian aristocratic life. Here they learned to replace the clan feud with the individual duel, an important shift from collective violence to individual responsibility and violence. Finally, the feuding clans, who now prided themselves on their courtly behavior, fought it out through the publication of dueling pamphlets, trying to best their rivals through elegant put-downs and masterly argument.

With the expansion of the state in many parts of Europe in the 16th and 17th centuries, violent and unruly behavior came to be seen as an affront to the prince or king. Manuals and proverbs about proper behavior proliferated, and townsfolk and merchants did their best to imitate the courtesy of court life.

Other scholars agree that the emphasis on self-control increased but think that it may have stemmed not only from the diffusion of courtly manners. "Both the Protestant Reformation and the Catholic Counter-Reformation put a lot of emphasis on individual conscience," said Tom Cohen, who teaches history at York University in Toronto. "The conscience becomes the internal gyroscope. There is the growth of introspection — the diary, the novel, the personal essay. Along with the kind of personal self-control that Norbert Elias describes."

Of course, Elias's civilizing theory still has its skeptics, with Mr. Roth of Ohio State University as a chief one. He argues there was little change in rates of violence between the 14th and the 16th centuries. "Then in the 17th century, there is a very big, dramatic drop," he says. "It's so sudden and rapid that it seems too hard to explain with a gradual, civilizing process. Here in the U.S. we have seen how quickly crime rates can both rise and drop, suggesting that countries don't become more or less civilized that quickly." Nonetheless, Mr. Roth agrees that the 17th-century decline in crime does partly fit Elias's idea of the pacifying effect of the rise of the state.

"I think it has to do with political stability and political legitimacy," he said. "It may have to do with the rise of nationalism and the sense of fellow feeling."

Conversely, Mr. Roth noted, one sees significant increases in violence at times of political tension when the legitimacy of government is under serious attack, before and after the Civil War, as well as after World War I in Europe. The fact that murder rates did not go down in Italy and Greece until the 19th centuries, when each country won its political independence and formed a modern national state, suggests that the decline may have had more to do with state formation than with the trickling down of court culture.

"The Elias theory, with its emphasis on civility, has great appeal in Europe because the Europeans have enjoyed this protracted period of peace," Mr. Roth said. "But national identity, state formation, political legitimacy all seem to play a role in why people kill their friends and neighbors or prey on strangers."

Copyright The New York Times Company. Reprinted from The New York Times, Arts & Ideas, of May 3, 2003.