This account (“The Crusaders in Mainz, May 27, 1096”) by Soloman Bar Samson of the Crusaders on their way to Jerusalem has come to us as another pogrom in a long history of pogroms spreading across the Pale, across the Alps, to the cities of Prague and Warsaw and Rome, on and on through the years to Kiev, and finally to Auschwitz and even afterwards to Kielce, where survivors of the camps were murdered as they attempted to return to their home.There was no Golem in Mainz in May of 1096. There was no Messiah, false or otherwise. There was no armed resistance hiding in the winding cobblestone streets of that gated city on the water, that city that had such a fine cathedral and even a palace for its archbishop.Emico, the leader of this particular band of crusading ruffians, religious zealots, monks, and unemployed mercenaries was real enough, and the story of the Crusaders in Mainz is well known and was recorded by others. Why wouldn’t we believe it? Here we have a group of armed men headed for Jerusalem enlisted in a holy war to reclaim the birthplace of Christ from infidels, to plunder for the churches of Europe, to seek the holy relics that waited in the land of the despised Christ rejecting Jews. Some of the wilding pack may have gone along for the adventure, some to enlarge their own fortunes. Some may have believed that they would honor their religion by massacring Jews in the sincere belief that Jews had killed their God and deserved therefore to die. This honor was expressed in the plunder and the murder of innocents, women and children; the slaughter of Jews without arms to protect themselves was a specialty of aroused crusaders.Small groups of merchants and scholars, wives and infants, wise or ignorant, loving or not, the Jewish citizens of Mainz gathered in the archbishop’s courtyard and gave him their jewelry, their silver, their coins in exchange for protection that in the end he could not give. After the townspeople opened the gates for Emico’s men, who burst into the archbishop’s courtyard brandishing weapons, calling for Jewish blood, the Jews cut their own throats and those of their babies and their children rather than allow the crusaders to slaughter them. No one is quite sure what happened to the treasure the Jews gave to the archbishop. Did it fall into Emico’s hands or did the archbishop hide it away for another project that would reflect glory on the archbishop himself in good time?The martyrdom of the Jews in the archbishop’s chambers deprived the murderers of the pleasure of their swords. But it also deprived the Jews there of life; perhaps some might have been saved, hidden away, escaped through a secret passage. If we count the number of souls lost that day and multiply by the generations, we can guess that hundreds of thousands of Jews more might have lived to perish in the ovens or perhaps flee to America. To consider this now is mad. To replay Jewish history as if one could say, no don’t, turn here, stop, is to flirt with insanity.The Evangelical ministers, the opportunistic politicians who claim that President Barack Obama should not have mentioned the Crusades when he was speaking of ISIS are ignorant of history or hope to perpetuate the most obvious lie that Christians always and only brim over with brotherly love. The Crusaders must certainly, wrapped in the holiness of their Christian faith, waving their flags, have resembled ISIS on the move—minus the tanks and the rifles, of course. To kill for your God, be he Allah or Jesus or Buddha or Vishnu, is a common human failure. Religion is charming when it comes to Easter bonnets, babies in mangers, wise men and stars, baskets of chocolate eggs, stockings hung on the chimney mantle. Less charming is the passion to harm the nonbeliever, the other believer, to rape and behead and mangle the children of the other God.It is true that the Nazis were not acting in the name of Christ. But they were raised as Christians, in Christian towns, with the image of Christ and the holy cross in their churches, in their psalms, in their holidays. The Germans of 1941 who watched as the trains were loaded with Jews, the apartments once owned by Jews occupied by Christian neighbors, the Jewish stores closed, books burned because they had Jewish authors, those Germans were all raised as Christians. So, while the Nazis did not construct Auschwitz in homage to Christ, they were nevertheless Christian men and women who staffed the camp, and Christmas- and Easter-celebrating souls who watched the smoke rise into the air with the ash of Jewish bodies spreading out over the countryside. Those who turned their eyes away were also raised in Christ. They believed they would go to heaven, and their heaven would be, like their country, free of Jews, a caliphate of Christian Aryans.Most of the Christian churches of the American South stood by while their parishioners lynched, segregated, whipped other human beings. Most of the Christian churches of the south supported the selling of human beings in a market like cattle. Most of the priests and the ministers, the Christian leaders, did not inform their flock that being a Christian included mercy and kindness and respect for all human life. The Christian moral leaders of the community did not for the most part deplore the Ku Klux Klan, which wore masks not unlike those of ISIS. Most of the Christian churches of the South did nothing to stop racial injustice, be it poll taxes or just separate water fountains, any more than most of the Germans protested against the slaughter of Jews.Murder in the name of religion is old, older than Mainz, older than the Romans throwing Christians to the lions. Murder demonstrates the ultimate power of my God over yours, and murder is proof of whose God rules and whose God is false and lies broken on the altar smashed into a thousand pieces.And while it is not Jesus Christ who was at fault, it was surely in his name and by his followers that countless Crimes Against Humanity were committed. The Crusaders didn’t know that such a crime was on the books, but they did know that killing was not encouraged by the Ten Commandments, that if the lion were to lie down with the lamb he ought not to chew on all the little bones. When we see the soldiers of ISIS, hiding behind their black face-masks, cold-eyed, dead-eyed, ready to behead with a knife, or douse a living man with gasoline, we know that Allah is not nearby. But it is not a fine thing when the passion for God inflames the weak heart of the constantly-angry, the ever-rageful, the “mine is better than yours,” men of God who have exchanged the prayer book for the knife and the love of neighbor for a fear of neighbor and a wonder at the natural world for a desire to own it, to trample it, to plunder it, to hoard it for oneself, to feel righteous in evil and feel good while sacking and spoiling and robbing.Yes, the Crusades are ancient news now. But it is nonsense to say that Christianity is pure as a newborn baby and the fundamentalist sects of ISIS cannot be compared to Christianity. But ISIS is not as foreign to us as we would like to think. Christians also slaughtered each other, the wars between the Protestants and the Catholics flared again and again leaving behind the usual human grief. Even after we knew how to prevent polio and fly into space, death followed Christian schisms in Ireland as if Christ had died for only part of the population.That is what Obama was saying. The enemy is not Islam, even if the men of ISIS and their followers write Allah’s name on their banners. It is the corruption of religion that rises again and again when kindness is misplaced and rage is fueled by hurt pride or wounded economies and shattered states or more intimate injuries that may not be reparable. We can stare with wonder and fear into the eyes of the masked ISIS warrior but we have to know that our history is also marked with horrors inflicted in the name of faith, just like the tragedy we see today in Mosul.And Jews, we have our murderers and zealots too. Baruch Goldstein. The folks in Israel who kept attempting to blow up the Dome of the Rock. The thugs who burned an Arab boy alive in a forest outside Jerusalem. The Jews of all countries who discount the humanity of the other. Yes, our own excesses of religion and nationalism, that dangerous elixir, have been minimal in comparison with the wounds inflicted on us. But we must fight the evil that is done in God’s name on both fronts, outside and inside, or else we will lose the battle.To read Soloman Bar Samson’s “The Crusaders in Mainz, May 27, 1096,” click here.***Like this article? Sign up for our Daily Digest to get Tablet Magazine’s new content in your inbox each morning.Anne Roiphe is a novelist and a journalist.