Do harsh words lead to violent acts? At a moment when hate speech seems to be proliferating, it's a question worth asking.
US Attorney-General Loretta Lynch recently expressed worry that heated anti-Muslim political rhetoric would spark an increase in attacks against Muslims. Some claim that last month's mass shooting in Colorado Springs was provoked by Ms Carly Fiorina's assertion that Planned Parenthood was "harvesting baby parts"; Ms Fiorina, a presidential hopeful, countered that language could not be held responsible for the deeds of a "deranged" man.
Similar debates have arisen over the beating of a homeless Hispanic man in Boston, allegedly inspired by the anti-immigration rhetoric of another presidential contender, Mr Donald Trump, and by the shooting deaths of police officers in California, Texas and Illinois, which some have attributed to anti-police sentiment expressed at Black Lives Matter protests.
No historian can claim to have insight into the motives of living individuals. But history shows that a heightening of rhetoric against a certain group can incite violence against that group, even when no violence is called for. When a group is labelled hostile and brutal, its members are more likely to be treated with hostility and brutality. Visual images are particularly powerful, spurring actions that may well be unintended by the images' creators.
The experience of Jews in mediaeval Europe offers a sobering example. Official Christian theology and policy towards Jews remained largely unchanged in the Middle Ages. Over roughly 1,000 years, Christianity condemned the major tenets of Judaism and held "the Jews" responsible for the death of Jesus. But the terms in which these ideas were expressed changed radically.
Before about 1100, Christian devotions focused on Christ's divine nature and triumph over death. Images of the crucifixion showed Jesus alive and healthy on the cross. For this reason, his killers were not major focus points in Christian thought. No anti-Jewish polemics were composed during these centuries; artworks portrayed his executioners not as Jews, but as Roman soldiers (which was more historically accurate) or as yokels. Though there are scattered records of anti-Jewish episodes like forced conversions, there is no consistent pattern of anti-Jewish violence.
In the decades around 1100, a shift in the focus of Christian veneration brought Jews to the fore. In an effort to spur compassion among Christian worshippers, preachers and artists began to dwell in vivid detail on Christ's pain. Christ morphed from triumphant divine judge to suffering human saviour. A parallel tactic, designed to foster a sense of Christian unity, was to emphasise the cruelty of his supposed tormentors, the Jews.
Partly out of identification with this newly vulnerable Christ, partly in response to recent Turkish military successes, and partly because an internal reform movement was questioning fundamentals of faith, Christians began to see themselves as threatened too.
In 1084 the pope wrote that Christianity "has fallen under the scorn, not only of the devil, but of Jews, Saracens, and pagans". The Goad Of Love, a retelling of the crucifixion that is considered the first anti-Jewish Passion treatise, was written around 1155-80. It describes Jews as consumed with sadism and blood lust. They were seen as enemies not only of Christ, but also of living Christians; it was at this time that Jews began to be accused of ritually sacrificing Christian children.
Ferocious anti-Jewish rhetoric began to permeate sermons, plays and polemical texts. Jews were labelled demonic and greedy. In one diatribe, the head of the most influential monastery in Christendom thundered at the Jews: "Why are you not called brute animals? Why not beasts?" Images began to portray Jews as hook-nosed caricatures of evil.
The first records of large-scale anti-Jewish violence coincide with this rhetorical shift. Although the pope who preached the First Crusade had called only for an "armed pilgrimage" to retake Jerusalem from Muslims, the first victims of the Crusade were not the Turkish rulers of Jerusalem but Jewish residents of the German Rhineland. Contemporary accounts record the crusaders asking why, if they were going to a distant land to "kill and to subjugate all those kingdoms that do not believe in the Crucified", they should not also attack "the Jews, who killed and crucified him".
Hundreds, perhaps thousands, of Jews were massacred in towns where they had peacefully resided for generations. At no point did the Christian authorities promote or consent to the violence.
Christian theology, which applied the Psalm verse "Slay them not" to Jews, and insisted that Jews were not to be killed for their religion, had not changed. Clerics were at a loss to explain the attacks. A churchman from a nearby town attributed the massacres to "some error of mind".
But not all the Rhineland killers were crazy. The crusaders set out in the Easter season. Both crusade and Easter preaching stirred up rage about the crucifixion and fear of hostile and threatening enemies. It is hardly surprising that armed and belligerent bands turned such rhetoric into anti-Jewish action.
For the rest of the Middle Ages, this pattern was repeated: Preaching about the crusades, proclamations of Jewish "enmity" or unsubstantiated anti-Jewish accusations were followed by outbreaks of anti-Jewish violence, which the same shocked authorities that had aroused Christians' passions were then unable to restrain.
This was evident in the Rhineland during the Second Crusade (1146), in England during the Third Crusade (1190), in Franconia in 1298, in many locales following the Black Death in 1348, and in Iberia in 1391.
Sometimes the perpetrators were zealous holy warriors, sometimes they were opportunistic business rivals, sometimes they were parents grieving for children lost to accident or crime, or fearful of the ravages of a new disease.
Some may well have been insane. But sane or deranged, they did not pick their victims in a vacuum. It was repeated and dehumanising excoriation that led those mediaeval Christians to attack people who had long been their neighbours.
Today's purveyors of anti-Muslim, anti-immigrant, anti-police and anti-abortion rhetoric and imagery may not for a moment intend to provoke violence against Muslims, immigrants, police officers and healthcare providers. But in the light of history, they should not be shocked when that violence comes to pass.
This article was first published on December 15, 2015.
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