If you have a chance to read the fourth issue of Dabiq, the official English-language magazine of the Islamic State, don’t. It will make you very ill.

Dabiq is a reasonably slick publication circulating as a PDF on the internet. It has lots of colour images; an historical feature; an interview with John Cantlie, the captive British journalist who features in ISIS videos; a letter from another captive, journalist Steven Sotlof, to his mother pathetically pleading for his life; followed by an double-page spread of his bloodied head lying on his corpse. And so on.

The 56 blood-soaked pages are meant to inspire Western “crusaders” with terror and ISIS followers with zeal to kill the infidels. “Every Muslim should get out of his house, find a crusader, and kill him,” reads a typical paragraph of religious fanaticism – which is followed by a shrewd marketing tip on branding: “It is important that the killing becomes attributed to patrons of the Islamic State who have obeyed its leadership. This can easily be done with anonymity. Otherwise, crusader media makes such attacks appear to be random killings.”

Most repugnant of all is a learned theological justification of enslaving Yazidi women and children captured when ISIS overran the province of Sinjar. The Yazidis follow an ancient religion related to Zoroastrianism, and are thus despised by Islamic extremists as pagans. According to Dabiq, “Yazidi women and children were then divided according to the Shari’ah amongst the fighters of the Islamic State” (after handing a fifth of their booty over to the Caliph as stipulated in the Qu’ran).

A few girls have escaped and confirmed these boasts.

The editors of Dabiq and the generals of ISIS are obviously intelligent men (all men, apparently). They have conquered vast swathes of territory and are conducting a clever public relations campaign. So how can they possibly defend selling women in a slave market? Slavery is the pinnacle of dehumanisation. It is a denial of the universal brotherhood of man, of the universality of human rights, and the reduction of human beings to commodities.

Blaming Islam is not the answer. ISIS claims to be reviving slavery in pious obedience to the Qu’ran. But outside of a few pockets of like-minded extremists, the Muslim world no longer practices it.

The answer is that ISIS has abandoned reason, except in the pragmatic sense of mastering technology and tactics for war. The Qur’an is their only law, a book written in the 7th Century for feuding desert tribes. They have no theology, for that involves the application of human reason to divine realities. As Benedict XVI said in his landmark speech in Regensberg in 2006, terrorists believe in “a capricious God, who is not even bound to truth and goodness. God’s transcendence and otherness are so exalted that our reason, our sense of the true and good, are no longer an authentic mirror of God.”

For the new atheists, the atrocities committed by ISIS prove that “religion poisons everything”, in the words of the late Christopher Hitchens. But if that is true, why is there no Christian counterpart of ISIS?

This question is best answered by studying the nearest counterpart Christianity has ever had to ISIS, the Teutonic Knights, a religious order whose mission was to convert or exterminate. The intriguing thing is how and why Christian intellectuals repudiated them.  

Early Christian writers condemned forced conversions. St Augustine of Hippo (354-430 AD) pointed out that if Christ had taught by appealing to human understanding, so should his followers. The early missionaries to the barbarian tribes of Western Europe, like Augustine of Canterbury, or Boniface, sought to win over Saxons and Germans by prayer and persuasion.

Unhappily, as Christendom spread, kings used faith as a way of uniting their domains. Charlemagne was the first to enforce baptism with the sword, although his court theologian, Alcuin, protested. The emperor’s new subjects should at least be catechised before becoming Christians, he said, for love was the proper way to embrace the faith.

Unfortunately, as Christian realms became more powerful and began to push east, toward the pagan Slavs, Alcuin’s advice was ignored. Nothing illustrates the issues at stake better than the controversy over the proselytising methods of the Knights. It may be a bit unfair to compare them to ISIS. Before World Wars I and II, many historians regarded their blood-and-iron crusades in the Baltic as a regrettable but necessary chapter in the centuries-long extension of civilisation to the east. The influential 19th Century historian Heinrich Von Treitschke (1834-96) described them as “the most stupendous and fruitful occurrence of the later Middle Ages – the northward and eastward rush of the German spirit and the formidable activities of our people as conquerer, teacher, discipliner of its neighbours”.

The Knights were a religious order which had emerged during the Crusades and had evolved into a fearsome band of warriors. After being expelled from Palestine by the Saracens, the Knights made themselves useful crusading in Prussia against the pagan Lithuanians. At the height of their power in the late 14th Century, they controlled a vast area along the Baltic coast from modern Germany to Estonia. The Polish Romantic poet Adam Mickiewicz described one of their warriors in his patriotic epic Konrad Wallenrod,

A German on his horse unmoved,
His eyes on enemy’s ramparts fixed,
He loads his gun and says his Rosary.

To the modern mind, the proselytizing methods of the Knights are the very antithesis of Christianity. And to Poles and Lithuanians of the 13th and 14th Centuries, they must have seemed just as appalling as ISIS does to us. But to their contemporaries in Western Christendom, the picture was not so clear.

The mists finally began to clear at the Council of Constance in 1414, when a debate began which led directly to our own views. It was a pivotal moment in the history of human rights.

Poland complained to the assembled bishops about the Knights. The Poles, who were on relatively good terms with their pagan neighbours, were regarded by the Knights as heretics because they had not laid waste the heathen lands. So they, too, were being attacked. Their foremost spokesman was Paulus Vladimiri (Paweł Włodkowic, 1370-1435), a distinguished scholar who was one of the first rectors of the Jagiellonian University in Krakow.

The Knights and their house theologians argued that Christ could not be reconciled with Satan or pagan idols; non-Christians and heretics had to be put to the sword because they were no better than brute beasts. Many bishops and kings agreed with them.

However, Paulus Vladimiri forged arguments based on reason and the Gospels which eventually convinced the Council to issue a partial condemnation of the Knights. Relying on a natural law theory developed extensively by Thomas Aquinas, he contended that the law of nations is part of the law of reason. Since non-believers are human beings, they have rights.

“And [the Knights], cruelly and inhumanly harassing those people, who though at that time were infidel but nevertheless, are our neighbours since they have the same nature as we have, and who at that time were living peaceably in their own dominions, killed and murdered them and oppress them in other ways with inhuman cruelly, both with regard to their persons and their possessions, all under the cloak of piety and the pretence of spreading the Catholic faith. All this is against the commandments of Christ and the divine law, and is in consequence gravely detrimental to the Christian religion and faith.”

Wars waged on peaceful pagans were unjust and the deprivation of life and property were nothing more than sinful murder and theft. The Knights were “wicked, illegal, unjust and outrageous”.

It is incomprehensible to modern Christians, but some theologians defended genocide as a religious obligation. Johannes Falkenberg, a Dominican, is the best known representative of this dark corner of Church history. He contended that the emperor was entitled to kill pagans simply because they were pagans, and Poles because they protected the pagans, and the Orthodox (whose allegiance was to Moscow rather than to Rome) because they were heretics and worse than pagans. Whoever exterminated the infidels would receive a heavenly reward. It sounds remarkably like ISIS’s promise of glorious martyrdom.

Paulus Vladimiri responded to Falkenberg’s vicious tirades by denouncing them as “pestiferous”, “repugnant to human and divine law” and – possibly worst of all – heretical.

“This doctrine is not only false and erroneous but, inasmuch as it is repugnant to the divine law, it is also heretical, impious and insane; inasmuch as it advocates the unjust killing of men in an unlawful way, it is dangerous, scandalous, temerarious and cruel; inasmuch as it deprives the Poles of legitimate defence contrary to natural law, it is seditious, injurious and disturbing to human society, and in consequence, offensive to honest ears and therefore should be condemned.”

He therefore requested the Council to denounce genocide as a crime under international law and a sin against Divine law.

Paulus Vladimiri was about 200 years ahead of his time. According to Stanislaus Belch, the author of a massive treatise on him, “He was the first to demonstrate the inhuman and un-Christian character of killing, exterminating, expelling or enslaving a nation, or national group, for ideological, racial or other reasons.”

The Polish scholar’s eloquence and rigour laid a foundation for later philosophers like Francisco de Vitoria and Hugo Grotius to elaborate a theory of human rights in the 16th Century prompted by the discovery of the New World.

Hundreds of years separate the atrocities of the Islamic State from the Order of Brothers of the German House of Saint Mary in Jerusalem (the official name of the Teutonic Knights), but there are some significant similarities. Both groups saw non-believers as less than human.

What gave Christians the intellectual clarity to reject the temptation of this dismal doctrine while ISIS and its Muslim sympathisers remain immersed in it after so many centuries?

First, because Christian tradition clearly teaches that belief is a grace granted freely by God. People who have not received that grace are still worthy of respect simply because they are human beings and children of a divine Father. Second, because Christian intellectuals had philosophical and theological tools; they were able to conduct rational debates about whether believers and non-believers shared a common humanity. They understood that the foundation of international law is a natural law derived from our inherent dignity.

In one of his speeches Benedict XVI quoted the words of the Byzantine emperor Manuel II Paleologus in 1391 which sum up the Christian approach then and now:

“God is not pleased by blood – and not acting reasonably is contrary to God’s nature. Faith is born of the soul, not the body. Whoever would lead someone to faith needs the ability to speak well and to reason properly, without violence and threats… To convince a reasonable soul, one does not need a strong arm, or weapons of any kind, or any other means of threatening a person with death…”.

The debate between Paulus Vladimiri and Johannes Falkenberg took place 600 years ago, but sadly it is still relevant. Whenever a religion excludes some humans from the human community, for whatever reason, terrible atrocities are bound to occur.

Michael Cook is editor of MercatorNet.

Michael Cook

Michael Cook is the editor of MercatorNet. He lives in Sydney, Australia.